Percents foldable 4.3, jan.26/10, tamika816

This goes in the percents foldable under 4.3 percent of a number.

Part A

Q1) Explain how you could use mental math to find each of the following:
a. 300% of 40. b. 0.5% of 120. c. 10.5% of 80.

A1a)

I use a ratio table to get my answer usually. In this one I went straight to multiplying 100% to 300% because it is an easy number to find. Then i multiply 40 by 3.

1b)

You can make the number a decimal by dividing it by 100. Then i multiplied the percent by 10, so its an easier number to work with. I took 1.2 then multiplied it by 5 which makes 6. And last divided it back down by 10.

1c)

I took a long way, but if you use numbers you work good with then it still works. I made 10% by dividing 100 by 10. Then I made 0.5% by dividing 1% by 2 and added 10% and 0.5% together to make 10.5%.

Q2) Describe 2 ways to find 6% of 129.

A)

one way is that you can go from 100 to 1(on a ratio table). Then multiply 1 by 5 to get 5 and add the 5% and 1% together to get 6%.
--Or you can divide 120 by 100% to get 1.2. Then multiply 1.2 with 6% which gives you 7.2.

Part B

Mr. Harbeck gave us this extra question.

Q3) How do you find 10%, 1%, 25%, 5%, 150%, and 0.5%?

A)
- 10%= 100/10.
- 1%= 100/100.
- 25%= 100/4 OR 100/2=50, then 50/2=25.
- 5%= 100/10=10, then 10/2=5.
- 150%= 100/2=50, then 50+100=150.
- 0.5%= 100/100=1, then 1/2=0.5.

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