Here is the link!
www.brainpop.com
Sunday, January 31, 2010
Sunday, January 24, 2010
Fractions, Decimals, Percents
I know fractions and decimals are not the most exciting concepts to learn, but they are important.
Trust me.
Use this as an example: 100% = 1.00 = 100/100
Percent means, "out of 100."
Some tips to remember;
Change Fraction to Decimal: "top in the box"
Example: 1/2 = 1 divided by 2 = 0.5
Change Fraction to a Percent: "top in the box", Move the decimal over to the RIGHT twice.
Example: 3/4 = 3 divided by 4 = 0.75 = 75%
Change Decimal to Fraction: Look at the place value and put it over either 10, 100, 1000, or so on
Example: 0.08 = 8/100 = 2/25
Change Decimal to Percent: Move the decimal over twice to the RIGHT
Example: 0.1 = 10 %
Change Percent to a Decimal: Move the decimal over tice to the LEFT
Example: 45.7% = 0.457
Change Percent to a Fraction: Put the number over 100 and reduce, if necessary, to its simplest form.
Example: 26% = 26/100 = 13/50
Trust me.
Use this as an example: 100% = 1.00 = 100/100
Percent means, "out of 100."
Some tips to remember;
Change Fraction to Decimal: "top in the box"
Example: 1/2 = 1 divided by 2 = 0.5
Change Fraction to a Percent: "top in the box", Move the decimal over to the RIGHT twice.
Example: 3/4 = 3 divided by 4 = 0.75 = 75%
Change Decimal to Fraction: Look at the place value and put it over either 10, 100, 1000, or so on
Example: 0.08 = 8/100 = 2/25
Change Decimal to Percent: Move the decimal over twice to the RIGHT
Example: 0.1 = 10 %
Change Percent to a Decimal: Move the decimal over tice to the LEFT
Example: 45.7% = 0.457
Change Percent to a Fraction: Put the number over 100 and reduce, if necessary, to its simplest form.
Example: 26% = 26/100 = 13/50
Friday, January 22, 2010
Scale Drawings
The scale drawing powerpoint is posted on my EDWEB (see link on the left).
Go to 8-2; FILES; click on the folder, and see my powerpoint!
Go to 8-2; FILES; click on the folder, and see my powerpoint!
Tuesday, January 19, 2010
Similar Figures
Similar Figures are figures with the same shape, but not necessarily the same size.
Sometimes, you have to find the missing number of a side, but it's not that hard! All you need to do is look at the corresponding shape, look for the corresponding side, and write out a proportion!
For example:
You can try some extra practice problems on the left labeled Similar Figures
Sometimes, you have to find the missing number of a side, but it's not that hard! All you need to do is look at the corresponding shape, look for the corresponding side, and write out a proportion!
For example:
You can try some extra practice problems on the left labeled Similar Figures
Wednesday, January 13, 2010
Proportions
Proportions show the equality of two ratios:
For example: 1/3 = 3/9
10/14 = 20/28
How can you find out if a proportion is equal?
There are many ways! Here are two.
1. Find the Cross Products (Cross Multiply)
Example: 1/3 = 3/9
1 x 9 = 3 x 3
9 = 9
2. Simplify either fraction and see if they are equal
Example: 10/16 = 30/48
10/16 = 5/8
30/48 = 15/24 = 5/8
So, 10/16 = 30/48
How do I set up a proportion with a WORD PROBLEM?
Example:
12 math problems in 45 min. How long does it take to do 20 math problems?
12 problems/45 min = 20 problems/x min
1. Cross multiply: 12 x x = 45 x 20
2. 12x = 900
3. Divide both sides by 12.
4. x = 75 min
CHECK YOUR WORK:
Plug in 75 into x. Are the ratios equal?
Try one on your own:
12 copies cost $0.66. Melissa needs 56 copies. How much should they cost?
............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
1. Set up the proportion:
12 copies/$0.66 = 56 copies/x
2. Cross multiply: 12 x x = 0.66 x 56
12x = 36.96
3. Divide both sides by 12.
4. x = $3.08
Did you get it right? Check your work!
For example: 1/3 = 3/9
10/14 = 20/28
How can you find out if a proportion is equal?
There are many ways! Here are two.
1. Find the Cross Products (Cross Multiply)
Example: 1/3 = 3/9
1 x 9 = 3 x 3
9 = 9
2. Simplify either fraction and see if they are equal
Example: 10/16 = 30/48
10/16 = 5/8
30/48 = 15/24 = 5/8
So, 10/16 = 30/48
How do I set up a proportion with a WORD PROBLEM?
Example:
12 math problems in 45 min. How long does it take to do 20 math problems?
12 problems/45 min = 20 problems/x min
1. Cross multiply: 12 x x = 45 x 20
2. 12x = 900
3. Divide both sides by 12.
4. x = 75 min
CHECK YOUR WORK:
Plug in 75 into x. Are the ratios equal?
Try one on your own:
12 copies cost $0.66. Melissa needs 56 copies. How much should they cost?
............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
1. Set up the proportion:
12 copies/$0.66 = 56 copies/x
2. Cross multiply: 12 x x = 0.66 x 56
12x = 36.96
3. Divide both sides by 12.
4. x = $3.08
Did you get it right? Check your work!
Sunday, January 10, 2010
Thursday, January 7, 2010
Unit Rate/Dimensional Analysis
Hello my dear 8-2's,
Today, we went over Dimensional Analysis. You can hear the Squirrel below teach a few steps, but because of limited amount of space given to speak, it'll go fast and you will need to hear it multiple times.
There is also a written explanation below, so please use that! Hope this helps!
Note: there is NO FRACTION bar in the sample problem below...just think invisibly!
Get a Voki now!
Example:
4o c/sec = ____ pints/min
1. Take the unit rate that is given:
40 c • ___ • ___
sec
2. What unit do you want to change first?
good! Pints!
So what do you need to get rid of? cups!
Where do you put cups to get rid of it? On the bottom!
What's the bigger unit? 1!
How many cups in 1 pint? 2!
40 c • 1 pint • ___
sec......2 c
3. Now that you got rid of the cups, what is the next unit you want? min!
So, what should we get rid of now? seconds!
What's the bigger unit? min!
How many seconds in 1 min? 60!
40 c • 1 pint • 60 sec
sec ......2 c....1 min
4. Multiply straight across, or cross cancel. Reduce in simplest form.
40 • 1 • 60 = 2400 = 1200 p/min
1 • 2• 1 ...... 2
and you DID IT!!! :)
Today, we went over Dimensional Analysis. You can hear the Squirrel below teach a few steps, but because of limited amount of space given to speak, it'll go fast and you will need to hear it multiple times.
There is also a written explanation below, so please use that! Hope this helps!
Note: there is NO FRACTION bar in the sample problem below...just think invisibly!
Get a Voki now!
Example:
4o c/sec = ____ pints/min
1. Take the unit rate that is given:
40 c • ___ • ___
sec
2. What unit do you want to change first?
good! Pints!
So what do you need to get rid of? cups!
Where do you put cups to get rid of it? On the bottom!
What's the bigger unit? 1!
How many cups in 1 pint? 2!
40 c • 1 pint • ___
sec......2 c
3. Now that you got rid of the cups, what is the next unit you want? min!
So, what should we get rid of now? seconds!
What's the bigger unit? min!
How many seconds in 1 min? 60!
40 c • 1 pint • 60 sec
sec ......2 c....1 min
4. Multiply straight across, or cross cancel. Reduce in simplest form.
40 • 1 • 60 = 2400 = 1200 p/min
1 • 2• 1 ...... 2
and you DID IT!!! :)
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