Pythagorean theorem is easy but check to see if you are answering the correct question

The following video demonstrates how to use a problem solving technique when solving word problems involving the Pythagorean Theorem.

Response to a question about percent benchmarks

A student asked me why it was fine to add the values of 20% of a number and 5% of a number to get 25% of a number. The following video has two examples that clarified it for the student.

Also, do not forget that you have a study island assignment. Also, if you did not complete the assignment we did today you may submit do so here.


To recieve our podcast on your computer click on this link or this one.

More on computing percents mentally

The following video describes how to find the percent of a number using various methods including mentally.

Computing percents mentally

To find the percent of a number easily you may use the fraction equivalents of percents. For example, 50% of 120 is the same as 1/2 of 120 or 60. You may also use 10% of that number to find other percentages. For example, to find 65% of 120 you may find 10% first. 10% of a number means that you divide that number into 10 equal parts, so 10% of 120 is 12. To get 60% of 120 you need 6 times more than the 10% that you have. Therefore, 60% of 120 is 12 times 6 or 78. To get the remaining 5% remember that 5% is half of 10%, so 5% of 120 is 6. To get 65% add what you have for 60% and 5%. The value that you get is 84. Please review the previous posts to see a video example of how to do this.


The homework for tonight is pg 270 numbers 8-25,36,37.

Finding the percent of a number information (part 3) and emergency lesson plans

Examples on how to find the percent of a number may be found in the following video.

Emergency lesson plans may be found here: Monday, Tuesday, Wednesday, Thursday, Friday.


Students have an assignment from study island that must be completed.

Also remember to continue to study and have your parents sign off on your study log.



Below are notes related to finding the percent of a number.

Finding the percent of a number information (part 2) and emergency lesson plans

The following video contains more information on how to quickly find the percent of a number.

Emergency lesson plans may be found here: Monday, Tuesday, Wednesday, Thursday, Friday.





Additional notes for part 2 are below.

Finding the percent of a number information (part 1) and emergency lesson plans

One method that may be used to find the percent of a number is to use benchmarks to calculate the percent of a number. For example 10% of 300 is 30. That means that 5% of 300 is half that. Therefore 5% of 300 is 15. We can use these relationships to find the percent of any number.

Emergency lesson plans may be found here: Monday, Tuesday, Wednesday, Thursday, Friday.



Additional notes for part 1 are below.

Cooking with proportions

Proportions, or equal ratios come up when we deal with food.

The following video demonstrates that.




If you would like more information about when you should set up a proportion please look here.
The homework tonight is to read pages 198 to 200 and do numbers 6 -25, 33-35.



The following poster describes when it would be appropriate to set up a proportion to solve a word problem.




Also, the following pdf was originally published by the Texas Education Agency. It is the April 2009 released TAKS test:



You may find more information about the TAKS test here: http://eigthgrademathmocity.wikispaces.com/TAKS+information

Computers use scale factor

The following video demonstrates how we use scale factor every time we use a computer.


Also, please sign in to your gaggle account tonight to complete the quiz that I emailed to you.

Scale factor is a proportional concept

If two figures are similar then there should be a scale factor that can be applied to one figure to get the sides of the other. The following video demonstrates how we can undertsand what similar figures really mean.

Scale Factor, Similarity, and proportions are related concepts

Scale factor describes the relationship between similar figures. The word "factor" is often connected to multiplication. Remember in elementary school you learned that factor times factor equals product. So in the statement "2 times 3 equals 6", 2 and 3 are factors of 6. Therefore scale factor tells us how two similar figures are related through multiplication. For example, if you have two similar figures where on the original figure a side is 2 feet and on the corresponding (matching side) of dilated figure is 6 feet, the scale factor is 3 because 2 times three equals 6. The following video shows a bit about how scale factor may be found in similar figures.

Remember that you DOthe scale factor. You write a ratio with the Dilated side over the corresponding or matching side on the Original figure.

Do not forget to complete the homework. The homework for tonight is page 209 numbers 13, 14, 16, 17, 20-24.

More on Dilations

Please click on the following link: http://eigthgrademathmocity.wikispaces.com/Scale+factor+questions

Similarity and Scale Factor

The Homework tonight is to read section 4-5 and to do pg. 209 numbers 5-12,18,19.

Here is the final exam schedule

The final exam schedule can be found below.

Your project is due tomorrow

Some of the projects that have been returned so far have been very well prepared. I am looking forward to the others that will be handed in tomorrow. If you need to email it to me you may find my email address on the school web site.

Today we discussed scale factor as it relates to similar figures.
To find the scale factor remember DO (dilation over the original) or NO (New over the Old)
You may find additional information about it here.



The notes from today are below.

Application of constant of proportionality

A proportional situation may be examined in a table. The following video shows that the constant of proportionality is the same as the unit rate and may be used to determine if a situation is proportional. Notice also how we use our TIPS problem solving format. At the end of the video I meant to say the problems on the left.)



The problem that was worked out is in the pdf below.

Proportions

There are several ways that we can use to determine whether a situation is proportional. One way is using the constant of proportionality. If a situation has a constant of proportionality it is proportional. If it does not have that constant then it is not proportional.This is is explained in the following video.

If you would like more information about proportions click this link or this link

Do not forget that your project is due on Friday. Also, I will be checking your study sheets. If you lost it, you may obtain a copy here. Or go to http://www.fortbend.k12.tx.us/campuses/mcms/TeacherDocuments.cfm?TeacherIndex=33314&ResourceIndex=33770
and click on study log.

Gallery walk

Do not forget that your district assessment is Tuesday of next week. On Monday please bring a signed note indicating that you have studied. You also need to bring your Post test paper back on Monday. Please review the links pertaining to rational numbers, Pythagorean theorem, and scientific notation.



Remember that you may also sign up for our podcast and receive our video lessons.

Operations on rational numbers part 3

The following video explains some of the questions that we have worked in class.

Some animation links

Your project is due 11/13/09. The description of your project may be found here. You may use animation as one way of presenting the information. If you do so you may click the following link. I will add more animation possibilities at another time.

Checkpoint tomorrow

The following video explains some questions that relate to your checkpoint tomorrow.




Below you will find a copy of the questions that are explained in the video.

More pythagorean theorem examples

Remember that each topic that we learn is not completely separate from other topics. Therefore, even though Pythagorean theorem is used many times as a formula it may also be interpreted geometrically. The following video demonstrates how we can connect those ideas.

Grades are exported this Friday

Your final opportunity to improve your grade will be this Friday. Please make sure that you return your unfinished test correction tomorrow. Also, please make sure that you practice applying the Pythagorean theorem because you will have questions related to it on your next checkpoint. This will be included in your major grades. Your homework is pg.165 numbers 8-19,33, and 34.






Below there is a description of your project that will be due November 13:

Pythagorean theorem geometrically speaking

The Pythagorean theorem is " a^2 + b^2 = c^2 " where a and b represent the length of legs and c represents the length of the hypotenuse. This formula is often read as "a squared plus b squared equals c squared." When it says "squared" geometrically you are using actual squares. When you add the areas of the squares on the legs it should equal the area of the square on the hypotenuse. If these areas do not add up then that means that the sides of those squares do not form a right triangle. The video below demonstrates that idea.


Also, the sides of the right triangle that form the 90 degree angle are called legs because they support the hypotenuse the same way that our legs keep us from falling. Also the hypotenuse comes from Greek words ( hypo - which means under, and teinein - which means to stretch) that give us the idea that it is the line that is stretched between the two legs of the right triangle.

No Homework tonight.



Also, don't forget that if you have trouble with pythagorean theorem you may see some more examples on our wiki.

Answers to our last test

Most periods did well on the test, however there were some popular mistakes. These mistakes are discussed in the video below. Also, do not forget that everything that we will do for the year is shown on the podcast and on our class wiki.

You may explore topics like scientific notation and pythagorean theorem on the wiki.

On each of those pages there are example TAKS problems, but there is also a separate page dealing with the TAKS test

Assessment tomorrow

Do not forget that you must have a study note signed by your parent when you take your assessment tomorrow. Also, please practice the concepts that we have discussed so far. I have posted a practice test in the box.net sidebar on the lower right side of your screen to help you practice your concepts for the test. Also, I have included a copy of it below.

Estimating square root word problems

You may have word problems involving estimating square roots. They may appear as a question in which you are estimating the length of the side of a square with a given area. For example, suppose you are asked the following " estimate the side length of a square if the area of that square is 14 square centimeters." In this case you should determine the perfect squares that this number falls between, then use that to estimate the square root of 14. First, 14 is between 9 and 16. So the square root of 14 is a number between 3 and 4. If you guess that this number is 3.7, you should multiply this number times itself to see if that product is close to 14.


The homework tonight is pg. 150 numbers 10 to 24 even. Also, do not forget study island.

More on estimating square roots

Today many of us were able to estimate the square root of irrational numbers. For those still experiencing difficulty just remember that your perfect squares tell you what numbers your estimated square root should be between. For example if we needed to find out the square root of 28, we know that 28 is between the perfect squares 25 and 36. Since the square roots of these numbers are 5 and 6 respectively, then the square root of 28 is going to be a number between 5 and 6. We can then guess and check our answer by multiplying that value by itself. The following video contains an example. You may also click here for more information on estimating irrational numbers.


The homework tonight is to read pages 148-9 and complete problems 9-25 (odd), 27-31, 33-42. Also, this week you have a study island assignment. The assignment is titled: "Rational and Irrational numbers 3." I will give you until next Friday to complete this study island assignment. Please remember that you may redo it for a higher grade. Do not guess because it will make your grade lower. Also you have a test this Friday.

Estimating square roots

Estimating square roots is a concept that has many applications. You may see this concept as a step in a word problem, or in problems testing your knowledge of the pythagorean theorem. It may even be used in a situation where the area of a square is given and you must find the length of the side. The homework from last week thursday was to do pg.136#27-36 and pg. 138#66-75. Tonight's homework is to describe :1. how to convert numbers from scientific notation to standard form. 2.a Strategy you may use when dealing with word problems involving elevation or temperature. Also, you will receive another study island assignment this week.

Our test today went well

About 95% of us know how to put fractions, decimals and percents in order. We were also very successful in determining the approximate location of a rational number on the number line. However, we need to work a little more on determining the appropriate operations in a word problem. Also, pay attention to the other words in a problem (the ones that are not math terms). These words may give additional information about what you should do.

The homework from yesterday is due tomorrow.

Also today we received our access code to view our grades online.

The following video will explain what you need to do to sign up.






This video explains a question that a student asked.

More on scientific notation

There are many ways to convert numbers from scientific notation to standard form. You could estimate the product and use that to verify your answer. For example 2.08 x 10^2 is close to 2 x 10^2. Since 2 x 10^2 is 200, you know that the answer to 2.08 x 10^2 is close to 200. So the answer is 208. Or you could move the decimal point according to the power of 10 that you have. If you have 3.16 x 10^3 you could move the decimal point three spaces to the right from where it is in 3.16. When you do that you end up with 3160.


The homework tonight is pg. 132 numbers 12-30 even.
Grades are exported Friday, please redo your study island assignment so that you can receive a higher grade. Also, please return the progress report that I handed out to you today. Make sure that it is signed by your parent. Also, test tomorrow.


If you do not have access to the textbook you may use the code (please see me) when you click the following link.

The following video is a student explaining one of the above ways to convert numbers from scientific notation.





The bottom of the paper was not visible in the video. But here is the paper that she was working on:

Recognizing a number that is in scientific notation

A number in scientific notation has the following requirements. One of the factors (usually the first number) is between 1 and 10. This number may be one but it may not be over 10. The other factor is a power of 10. The exponent may be any integer.

For example 9.7 x 10^5 is correct scientific notation, but 97 x 10^4 is not.


Homework tonight is pg. 132 numbers 11-29 (odd) and numbers 30-34, 36-44.

Also, don't forget grades for this progress report get exported this friday. You must also complete another study island assignment before friday at 5 p.m.

Yes we are still discussing rational numbers

We need to be able to look at a problem solving situation and determine what operations need to be done, and apply those operations to the information that the problem gives.


You have another web assignment on study island. You need to complete this assignment by Sunday. The assignment is titled: "Rational numbers assignment 2". Do not wait until then to do it. Remember that you have many opportunities to redo the assignment and receive a high grade.

No Homework tonight.

Open house is tonight.

Practice your problem solving skills

One plan you may use in solving a problem is to look for a pattern in the information and use it to find your answer. After you do this check your answer for reasonableness.


Homework tonight is to complete sections 1-6 and 2-8 in the glencoe study guide and intervention book. You may access these on the wiki Click the link that says "do you need step by step explanations on chapter problems?"

Also, do not forget that many of the topics we will discuss this year are already explained on our class wiki and on our podcast.

We will do a project involving creating a scripted situation explaining what we have learned so far. If you have an opportunity you may want to start playing around with this free text to action site at this link

Rational number suggestions

If you have a problem that seems difficult, don't forget that you may change it to an equivalent problem to find the solution. For example if you did not know how to calculate -3.5 - (-2.7) you could try the problem without decimals to see what you should do. - 3 - (-2) is an easier problem to work out.


Do not forget that your web assignment is due sunday. Don't procrastinate, as you have known since monday that this assignment is due. Also, your homework this weekend is to complete pg. 113 numbers 1,2,4-16.

Answering questions on rational numbers

You may receive the videos on this blog by downloading our podcast on itunes.

Homework tonight is to complete the sheet "word problem practice section 2-5". . Remember that if you received a poor grade on study island, you may redo it some time before sunday.

The following video explains some questions that were asked about the homework. If you have any additional questions, or if there are examples that you would like to see worked out, please visit our question area and post a comment at the bottom of the screen.

If you needed to see question 39 worked out visit the post for Monday.







Here are the lyrics the the integer song made by CORE educational tools.

Open publication - Free publishing - More rational

Even more on operations on rational numbers- integer rules

Don't forget to hand in your test corrections by tomorrow. Also, remember that your web assignment is due by sunday. I extended the date to allow those that do not have internet access at home to make arrangements to complete the assignment. Please let me know if you have any technical issues in accessing study island.


Homework tonight : pg 110 numbers 29-41,43,46-59
you may also want to listen to the integer song to remember how to use integers. The integer song was made by CORE (http://www.educationaltools.org/core/).

Addition and subtraction of like fractions (yes you still do this in grade 8)

The difference between adding these fractions in elementary school and doing so in grade 8 is that you will have to use your integer rules to know how to add them. remember that when adding integers if the signs are the same add the numbers and keep the sign. If they are different, subtract the numbers and keep the sign.

You can change any subtraction problem to addition using keep change change.

Homework tonight : read pg. 108-109 do numbers 11-28,44,45


Test corrections due wednesday.



Web assignment due friday : Go to study island and do the assignment ocalled "Operations on rational numbers".


The following video explains how to do the homework for tonight.

How do you divide rational numbers that are in fraction form?

To divide rational numbers that are in fraction form you just need to change the problem to multiplication using the multiplicative inverse. You should do KEEP CHANGE FLIP. Keep the first fraction the same, then change the operation to multiplication and flip the second fraction.

More on operations on rational numbers- multiplying fractions

To multiply fractions remember that like signs have a positive answer when multiplying, and unlike signs have a negative answer. Also to get the product you must multiply the numerators then multiply the denominators, and simplify as necessary.

The homework tonight is to read pg. 102 - 104 and do numbers 13-36,47,48

Also define : multiplicative inverse and reciprocal.

Identifying words or ideas that indicate addition, subtraction, or multiplication

The key to knowing what operation to do in a word problem is to understand what information is actually being given (what ideas or processes is the question indicating). Along with that you should know what operation certain key words indicate.


No Homework tonight.

Operations on rational numbers

The assignment today was to complete all problems for section 2-2 in the glencoe study guide and intervention book.

Also students were to complete the first four problems on page 13 of the glencoemastering the TAKS book.


Tonight's homework is to read pg. 96-98 and do numbers 12-29,55,56

If you do not remember how to access the textbook online click here.


Since we will soon discuss operations on rational numbers you should review how to perform operations on integers. Also, start to think about when a word problem requires addition, subtraction, multiplication, or division.

Questions about wednesday night's homework

The following video explains some of the questions that students had trouble with on the homework that was given on Wednesday 9/2/09

About the test

Unfortunately I was unable to upload a practice test and answers.
The answers to Friday's test are below if you would like to print a copy go to the sidebar and click inside of the box titled "box.net"

Open publication - Free publishing - More rational

The following video explains how the test questions should have been worked out and explains some of the errors in the above document. Unfortunately, there are also a few typing errors "fraction decimal" should just be "decimal."



If you would like to learn more about rational numbers click here or here. This link contains examples of how this question may be tested on the TAKS test.

Rational number comparison review

You have a test tomorrow.



The following are the homework questions that you should answer tonight:
(Click on the image to enlarge it)
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Open publication - Free publishing - More rational

Test this friday

Do not forget that you have a test this friday. Please check the blog later, I will post a practice test with answers.

Tonight's homework is from the textbook : Do page 94 numbers 30-36, 38, 42-53 and read page 96 - 98.



The following are questions that we did today. They are answered in the video above.

Open publication - Free publishing - More rational

More on rational numbers

There will be a test on friday regarding comparing and ordering rational numbers, and placing them on a number line.

If you have any unresolved questions about rational numbers please click here to ask.

Tonight's homework is is to answer the following questions:
(give examples to support your explanation)

1. What is a rational number?

2. How do you put rational numbers in order?

3. How do you decide where to put rational numbers on a number line?


Also, the following are the answers to some of the questions that were posed at the end of the video in this post.

Putting rational numbers on a number line

To put rational numbers on a number line you may convert them to decimals, then use what you know about money to put them in order. Remember also that the negatives are like a mirror for the positives. If 0.75 is close to 1.00 or 1 dollar then -0.75 is close to
-1.00.

For more information about rational numbers click here.




Tonight's homework (section 2-2) in the textbook. Read page 91-93. Do numbers 10-29, 39-41


If you do not have access to the textbook you may see me for the code and enter it when you click the following link.

Here is what your screen should look like:

Comparing and ordering rational numbers with negative decimals

We discussed comparing and ordering rational number. In sixth and seventh grade students were asked to put positive rational numbers (fractions, decimals, and percents) in order. In eighth grade they are asked to do the same but with some negative rational numbers mixed into the problems. What students need to remember is that you put these values in order the same way that you put integers in order.

To learn more view the video below or click on the following link: Comparing fractions decimals and percents





Here is a list of some of the common fraction decimal percent equivalencies:

Advice from students last year

The following presentation contains advice that some of last year's students gave to the incoming eighth grade students.

How do we use class time

As the school year is about to begin we should think about how we use or time. The following slides will help us to reflect on how well we are using our time, and if we have room for improvement.