Fractions, Decimals, and Percents

# Fractions, Decimals, and Percents

## Fractions, Decimals, and Percents

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1. Fractions, Decimals, and Percents

2. How to change percentages into fractions and decimals • Percent – a ratio that compares a number to 100. • The % says, “per hundred.” • For example, 47%, is simply another way of writing the fraction 47/100

3. Fractions to Percents Ex 1: Annie answered 90 out of 100 questions correctly. Since the fraction already has a denominator of 100, you automatically have the percentage!

4. Fractions to Percents Ex 2: On average, 50.5 out of 100 students own a pet. Since the fraction already has a denominator of 100, you automatically have the percentage!

5. Fractions to Percents Ex 3: Write as a percent. Find an equivalent fraction that has a denominator of 100 x5 x5

6. Fractions to Percents x5 x5 x20 x20 x4 x4

7. Practice: Express as a percent. x 25 1 25 25 % = = 4 100 x 25

8. Practice: Express as a percent. x 20 60 3 60 % = = 5 100 x 20

9. Decimals to Percents To change a decimal into a percentage, you multiply by 100 X 100 0.23 23%

10. Decimals to Percents 0.56 x 100 = 56% 0.8 x 100 = 80% 0.007 x 100 = 0.7% 2.5 x 100 = 250% 14.6 x 100 = 1460%

11. Decimals to Percents What is another way to change decimals to percents? * Move decimal point 2 places to the right * Add the % sign

12. Example: Express 0.375 as a percent Move decimal point 2 places to the right and add the % sign. 37.5 % 0.375 = Convert 2.867 to a percent 286.7 % 2.867 =

13. Decimals to Percents 62.5 % 0.625 = 70 % .7 0 = Make sure there are at least two digits after the decimal points - add zero where needed (this does not change the value of the number).

14. Fractions to Percents 1 0.25 = 4 Convert decimal to percent by moving 2 decimal places to the right and adding % sign or by multiplying by 100 and adding % sign 0.25 25 % or = 0.25 X 100 25 % =

15. Fractions to Percents 87.5 % 0.875 = 125 % 1.25 = 37.5 % .375 =

16. Percents to Fractions How do I express percents as fractions? * Write the percent over 100 * Simplify the fraction

17. Percents to Fractions 30 3 30 % = = 100 10 3 6 6 % = = 100 50 180 180 % = 100

18. Percents to Fractions 35 7 35 % = = 100 20 1 5 5 % = = 100 20 130 13 130 % = = 100 10

19. So to write a percentage as a fraction, you simply put it over 100 like this: 24% = 24/100 12/50 6/25 24% = 24/100 Yes, but remember to write the fraction in its simplest form

20. Percents to Decimals How do I express Percents as decimals? * Move decimal 2 places to the left * Remove the % sign * Or divide by 100

21. Example: Express 56.25 % as a decimal Move decimal point 2 places to the LEFT and remove the % sign. 56.25 % .5625 = 1.25 125 % =

22. Percents to Decimals 97 % .97 = .035 0 3.5 % = 42.8 % .428 =

23. You Should Know Decimal to a percentage X 100 A percentage is a special fraction. 23% = 23/100 Percentage to a decimal ÷ 100

24. Complete the Table 25% 6/25 36% 11/20 83.3% 75% 70% 17/100 39/50 50%

25. Complete the Table 0.27 87% 8% 0.02 42% 0.55 0.084 .4% 0.17 71% 0.98 7%