chapter 5 equivalents and percents. percent percent means “per centum” or “per hundred” or...
TRANSCRIPT
Chapter 5Chapter 5
Equivalents and PercentsEquivalents and Percents
PercentPercent
Percent means “per centum” or “per Percent means “per centum” or “per hundred” or /100.hundred” or /100.
28 28 = 28%, = 28%, 396396 = 396%, = 396%, .9.9 = .9 % = .9 %
100 100 100
1. Write 1. Write 156156 as a percent as a percent 100 100
2. Write 2. Write 7171 as a percent. as a percent. 100 100
3. Change 3. Change 17.617.6 to a percent. to a percent. 100 100
How do you change a percent How do you change a percent to a decimal?to a decimal?
Going from Percent to DecimalGoing from Percent to Decimal
Move the decimal point 2 places to the left Move the decimal point 2 places to the left then drop the % signthen drop the % sign
72% = .7272% = .72 .25% = .0025.25% = .0025 124% = 1.24124% = 1.24 2% = .022% = .02
4. Change 53.7% to a 4. Change 53.7% to a decimal.decimal.
5. Change 0.76% to a 5. Change 0.76% to a decimal.decimal.
6. Change 134% to a decimal.6. Change 134% to a decimal.
How do you change a decimal How do you change a decimal to a percent?to a percent?
Going from Decimal to PercentGoing from Decimal to Percent
Move the decimal point 2 places to the Move the decimal point 2 places to the right then add the % sign (move to the % right then add the % sign (move to the % sign)sign)
.24 = 24%.24 = 24% .024 = 2.4%.024 = 2.4% .0024 = .24%.0024 = .24% 1.25 = 125%1.25 = 125%
7. Write 0.36 as a percent.7. Write 0.36 as a percent.
8. Write 7.3 as a percent.8. Write 7.3 as a percent.
9. Write 0.0072 as a percent.9. Write 0.0072 as a percent.
How do you change a percent How do you change a percent to a fraction?to a fraction?
Changing a Percent to a FractionChanging a Percent to a Fraction
Change to a decimal first, then write as a Change to a decimal first, then write as a fraction and simplify.fraction and simplify.
37% = .37 = 37% = .37 = 3737 , 75% = , 75% = 7575 = = 33
100 100 4100 100 4
43.5% = .435 = 43.5% = .435 = 435435 = = 8787
1000 200 1000 200
325% = 3.25 = 3 325% = 3.25 = 3 2525 = 3 = 3 11
100 4100 4
10. Change 2% to a fraction. 10. Change 2% to a fraction. Reduce to lowest terms.Reduce to lowest terms.
11. Change 0.7% to a 11. Change 0.7% to a fraction. Reduce to lowest fraction. Reduce to lowest terms.terms.
12. Change 225% to a 12. Change 225% to a fraction. Reduce to lowest fraction. Reduce to lowest terms.terms.
Changing a Percent to a FractionChanging a Percent to a Fraction
If the percent contains a mixed number, If the percent contains a mixed number, change the mixed number into an change the mixed number into an improper fraction and multiply by 1/100. improper fraction and multiply by 1/100. Simplify.Simplify.
3 3/8% = 27/8 x 1/100 = 27/8003 3/8% = 27/8 x 1/100 = 27/800
16 7/8% = 135/8 x 1/100 = 135/800 = 16 7/8% = 135/8 x 1/100 = 135/800 = 27/10027/100
13. Change 3 1/5% to a 13. Change 3 1/5% to a fraction.fraction.
14. Change 7 5/8 % to a 14. Change 7 5/8 % to a fraction.fraction.
How do we change a fraction How do we change a fraction to a percent?to a percent?
Changing a Fraction to a PercentChanging a Fraction to a Percent
Change the fraction to a decimal, then Change the fraction to a decimal, then change the decimal to a percent.change the decimal to a percent.
.375.375 3/8 = 8 3.000 .375 = 37.5%3/8 = 8 3.000 .375 = 37.5% 2424 6060 5656 4040 4040 00
Changing a Fraction to a PercentChanging a Fraction to a Percent
Change the fraction to a decimal, then Change the fraction to a decimal, then change the decimal to a percent.change the decimal to a percent.
7/40 = .175 = 17.5%7/40 = .175 = 17.5%39/50 = .78 = 78%39/50 = .78 = 78%
If a decimal repeats infinitely, round off to If a decimal repeats infinitely, round off to nearest hundredth of a percent.nearest hundredth of a percent.
1/6 = .16666… 1/6 = .16666… ≈ .1667 = 16.67%≈ .1667 = 16.67%
15. Change 15. Change 88 to a percent. to a percent. 15 15
16. Change 16. Change 55 to a percent. to a percent. 16 16
EquivalentsEquivalents
Change from fraction to Change from fraction to decimal to percent, given one decimal to percent, given one formform
17. Change 27.5% to an equivalent 17. Change 27.5% to an equivalent
A) fraction reduced to lowest A) fraction reduced to lowest termsterms
B) decimalB) decimal
18. Change 0.825 to an equivalent 18. Change 0.825 to an equivalent
A) fraction reduced to lowest A) fraction reduced to lowest termsterms
B) percentB) percent
19.19. Change 9/5 to an equivalentChange 9/5 to an equivalent
A) decimalA) decimal
B) percentB) percent
20. Change to a common value 20. Change to a common value and put in order from smallest and put in order from smallest to largest. to largest.
3/16 .17 20% 3/16 .17 20%
21. Change to a common value 21. Change to a common value and put in order from smallest to and put in order from smallest to largest. largest.
15/25 59/100 61 2/3% .6215/25 59/100 61 2/3% .62
Solving Percent Problems with the Solving Percent Problems with the Equation MethodEquation Method
Note the Note the mathematical mathematical equivalent for the equivalent for the following words.following words.
ofof Multiply (X)Multiply (X)
isis ==
whatwhat NN
findfind N=N=
Solving Percent Problems with the Solving Percent Problems with the Equation MethodEquation Method
What is 5% of 19?What is 5% of 19?N = 5% x 19N = 5% x 19N = .05 x 19N = .05 x 19N = .95N = .95 Find 160% of 500Find 160% of 500N = 160% x 500N = 160% x 500N = 1.60 x 500N = 1.60 x 500N = 800N = 800
Solving Percent Problems with the Solving Percent Problems with the Equation MethodEquation Method
12 is 0.6% of what?12 is 0.6% of what?12 = 0.6% x N12 = 0.6% x N12 = .006 x N12 = .006 x N 1212 = = .006 x N.006 x N.006 .006.006 .0062000 = N2000 = N What percent of 5000 is 3.8?What percent of 5000 is 3.8?N x 5000 = 3.8N x 5000 = 3.8N x 5000N x 5000 = = 3.83.8 5000 50005000 5000N = .00076N = .00076N = .076%N = .076%
22. 160% of what number 22. 160% of what number is 152? is 152?
23. Find 0.6% of 45.23. Find 0.6% of 45.
24. What percent of 40 24. What percent of 40 is 160?is 160?
Solving Percent Problems with Solving Percent Problems with Proportion MethodProportion Method a/b = p/100a/b = p/100
a = amounta = amount
b = baseb = base
p = percent number p = percent number
Note “a” is associated with “is” It’s on the topNote “a” is associated with “is” It’s on the top
“ “b” is associated with “of.” It’s on the b” is associated with “of.” It’s on the bottom. Remember a, e, i, o, u: i before obottom. Remember a, e, i, o, u: i before o
Solving Percent Problems with Solving Percent Problems with Proportion MethodProportion Method
Note “a” is associated with “is”Note “a” is associated with “is”
“ “b” is associated with “of”b” is associated with “of”
What is 52% of 300?What is 52% of 300?
isis = = pp
of 100of 100
NN = = 5252
300 100300 100
Identify p b aIdentify p b a
25. What is 60% of 7025. What is 60% of 70
26. 68 is what percent of 72?26. 68 is what percent of 72?
27. 354 is 40% of what number?27. 354 is 40% of what number?
28. What percent of 40 is 8?28. What percent of 40 is 8?
29. 12% of what number 29. 12% of what number is 15? is 15?
30. What is 25% of 92 ?30. What is 25% of 92 ?