Chapter 5 Equivalents and Percents

Percent  Percent means “per centum” or “per hundred” or /100.  28 = 28%, 396 = 396%,.9 =.9 %

1. Write 156 as a percent 100

2. Write 71 as a percent. 100

3. Change 17.6 to a percent. 100

 How do you change a percent to a decimal?

Going from Percent to Decimal  Move the decimal point 2 places to the left then drop the % sign  72% =.72 .25% =.0025  124% = 1.24  2% =.02

4. Change 53.7% to a decimal.

5. Change 0.76% to a decimal.

6. Change 134% to a decimal.

 How do you change a decimal to a percent?

Going from Decimal to Percent  Move the decimal point 2 places to the right then add the % sign (move to the % sign) .24 = 24% .024 = 2.4% .0024 =.24%  1.25 = 125%

7. Write 0.36 as a percent.

8. Write 7.3 as a percent.

9. Write as a percent.

 How do you change a percent to a fraction?

Changing a Percent to a Fraction  Change to a decimal first, then write as a fraction and simplify.  37% =.37 = 37, 75% = 75 = % =.435 = 435 = % = 3.25 = 3 25 =

10. Change 2% to a fraction. Reduce to lowest terms.

11. Change 0.7% to a fraction. Reduce to lowest terms.

12. Change 225% to a fraction. Reduce to lowest terms.

Changing a Percent to a Fraction  If the percent contains a mixed number, change the mixed number into an improper fraction and multiply by 1/100. Simplify.  3 3/8% = 27/8 x 1/100 = 27/800  16 7/8% = 135/8 x 1/100 = 135/800 = 27/100

13. Change 3 1/5% to a fraction.

14. Change 7 5/8 % to a fraction.

 How do we change a fraction to a percent?

Changing a Fraction to a Percent  Change the fraction to a decimal, then change the decimal to a percent  3/8 = = 37.5%

Changing a Fraction to a Percent  Change the fraction to a decimal, then change the decimal to a percent. 7/40 =.175 = 17.5% 39/50 =.78 = 78%  If a decimal repeats infinitely, round off to nearest hundredth of a percent. 1/6 =.16666… ≈.1667 = 16.67%

15. Change 8 to a percent. 15

16. Change 5 to a percent. 16

Equivalents  Change from fraction to decimal to percent, given one form

17. Change 27.5% to an equivalent A) fraction reduced to lowest terms B) decimal

18. Change to an equivalent A) fraction reduced to lowest terms B) percent

19.Change 9/5 to an equivalent A) decimal B) percent

20. Change to a common value and put in order from smallest to largest. 3/ %

21. Change to a common value and put in order from smallest to largest. 15/25 59/ /3%.62

Solving Percent Problems with the Equation Method  Note the mathematical equivalent for the following words. of Multiply (X) is= whatN findN=

Solving Percent Problems with the Equation Method  What is 5% of 19? N = 5% x 19 N =.05 x 19 N =.95 Find 160% of 500 N = 160% x 500 N = 1.60 x 500 N = 800

Solving Percent Problems with the Equation Method  12 is 0.6% of what? 12 = 0.6% x N 12 =.006 x N 12 =.006 x N 12 =.006 x N = N What percent of 5000 is 3.8? N x 5000 = N = N =.076%

% of what number is 152?

23. Find 0.6% of 45.

24. What percent of 40 is 160?

Solving Percent Problems with Proportion Method  a/b = p/100 a = amount b = base p = percent number Note “a” is associated with “is” It’s on the top “b” is associated with “of.” It’s on the bottom. Remember a, e, i, o, u: i before o “b” is associated with “of.” It’s on the bottom. Remember a, e, i, o, u: i before o

Solving Percent Problems with Proportion Method Note “a” is associated with “is” “b” is associated with “of” “b” is associated with “of” What is 52% of 300? is = p is = p of 100 N =

Identify p b a 25. What is 60% of is what percent of 72? is 40% of what number?

28. What percent of 40 is 8?

29. 12% of what number is 15?

30. What is 25% of 92 ?