Math Class: May 2009

Friday, May 29, 2009

Comparing Fraction Decimal and Percent

Put every rational number in the same form then compare them.

How can you write numbers in scientific notation?

Remember that positive exponents are for whole numbers and negative exponents give decimals less than 1. Also, the first number in your scientific notation is more than one but less than 10.

How do you know what to do when asked for the scale factor of a dilation?

Remember NO, New over Old. Put the new amount over the old amount.

Thursday, May 28, 2009

Central Tendency and Range

Central Tendency summarizes information in a data set, or list of numbers. It may be used in sports, education, or any field that data is important. It includes mean median and mode. Sometimes the range is also considered.

How can you tell if you must use the Pythagorean Theroem?

The Pythagorean Theorem should be used whenever the problem implies that there is a right triangle, and you need to find the length of one side.

Wednesday, May 27, 2009

How do you reflect over a line or axis?

The line or axis is like a mirror. A point is the same distance from the mirror as its image.

http://www.lakaw.com/2008/05/easy-way-to-teaching-kids-math.html

How do you convert fractions decimals and percents? Part 1

This is useful to know when we need to compare order fractions, decimals and percents. The attached link is the first of two videos

How can you visualize a figure from different views?

Having a good imagination helps, but if this is a problem count what you have on each side of the figure.

How does scale factor affect volume?

To apply a scale factor to volume cube that scale factor (SF * SF * SF) then multiply that number by the volume to get the new volume.

How to find the surface area of a prism.

You may find the area of each face and add them together, or you may use the formulas. Make sure that you know what the base is, and how to find its perimeter and area.

What are dimensions?

Dimensions can be a complex mathematical subject. However, in middle school you just need to know that dimensions measure the figure. Length, Width and Height are dimensions. The diameter and the radius provide the dimensions for a circle.

Tuesday, May 26, 2009

How do you find the area of composite figures.

Composite figures have several basic shapes attached to make the composite shape. Sometimes you have to use your imagination to see them, but when you do add the area of each shape to get the total area of the figure.

How do you divide decimals?

Move the decimal in the divisor and dividend the same number of times to make the divisor a whole number. Then divide as normal.

How do you know you have to set up a proportion?

Look for key words or ideas that indicate a comparison.

How do yo find surface area and volume when a figure is changed by a scale factor?

The units that we use to measure area and volume give us an idea of how to figure out area and volume after a scale factor.

How can you tell when you are supposed to set up a proportion?

Look for key words and ideas that indicate comparing two different quantities with a constant ratio.

Probability of Dependent events.

This is another student explanation. Notice that the probability of dependent events is done similarly to independent events, but the second probability has a lower denominator.

Probability of Independent events

The video embedded in this link was made by one of our eighth grade students. It explains that the probability of two independent events is the product of each probability.