Chapter 5 Equivalents and Percents Percent Percent means

Chapter 5 Equivalents and Percents

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

1. Write 156 as a percent 100

2. Write 71 as a percent. 100

3. Change 17. 6 to a percent. 100

ØHow do you change a percent to a decimal?

Going from Percent to Decimal Ø Move the decimal point 2 places to the left then drop the % sign Ø 72% =. 72 Ø. 25% =. 0025 Ø 124% = 1. 24 Ø 2% =. 02

4. Change 53. 7% to a decimal.

5. Change 0. 76% to a decimal.

6. Change 134% to a decimal.

ØHow do you change a decimal to a percent?

Going from Decimal to Percent Ø Move the decimal point 2 places to the right then add the % sign (move to the % sign) Ø. 24 = 24% Ø. 024 = 2. 4% Ø. 0024 =. 24% Ø 1. 25 = 125%

7. Write 0. 36 as a percent.

8. Write 7. 3 as a percent.

9. Write 0. 0072 as a percent.

ØHow do you change a percent to a fraction?

Changing a Percent to a Fraction Ø Change to a decimal first, then write as a fraction and simplify. 37% =. 37 = 37 , 75% = 75 = 3 100 4 43. 5% =. 435 = 87 1000 200 325% = 3. 25 = 3 1 100 4 Ø

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 Ø If the percent contains a mixed number, change the mixed number into an improper fraction and multiply by 1/100. Simplify. Ø 3 3/8% = 27/8 x 1/100 = 27/800 Ø 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.

ØHow do we change a fraction to a percent?

Changing a Fraction to a Percent Ø Change the fraction to a decimal, then change the decimal to a percent. . 375 Ø 3/8 = 8 3. 000. 375 = 37. 5% 24 60 56 40 40 0

Changing a Fraction to a Percent Ø Change the fraction to a decimal, then change the decimal to a percent. 7/40 =. 175 = 17. 5% 39/50 =. 78 = 78% Ø 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 ØChange 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 0. 825 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. 3/16 . 17 20%

21. Change to a common value and put in order from smallest to largest. 15/25 59/100 61 2/3%. 62

Solving Percent Problems with the Equation Method Ø Note the mathematical equivalent for the following words. of is what find Multiply (X) = N N=

Solving Percent Problems with the Equation Method What is 5% of 19? N = 5% x 19 N =. 05 x 19 N =. 95 Ø 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. 006 2000 = N Ø What percent of 5000 is 3. 8? N x 5000 = 3. 8 5000 N =. 00076 N =. 076%

22. 160% of what number is 152?

23. Find 0. 6% of 45.

24. What percent of 40 is 160?

Solving Percent Problems with Proportion Method Ø 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

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

Identify p 25. What is 60% of 70 26. 68 is what percent of 72? 27. 354 is 40% of what number? b a

28. What percent of 40 is 8?

29. 12% of what number is 15?

30. What is 25% of 92 ?