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Simplifying fractions Percent to decimal Percent to fractionHere you will learn about percent increase, including how to increase a value by a given percentage, use multipliers to calculate percentage increase and work out percentage change.
Students will first learn about percent increase as part of ratios and proportions in the 7th grade.
Percent increase means adding a given percentage of a value onto the original value. To do this, you can either calculate the given percentage of the value and then add it on to the original value or use a percent as a decimal.
For example,
Increase \$30 by 20\%.
Add on the percent | Percent as a decimal |
---|---|
\begin{aligned} & 10 \%=\$ 3 \\\\ & 20 \%=\$6 \end{aligned} So \$30 increased by 20\% = \$ 30+\$ 6=\$ 36. | \begin{aligned} & 100 \%+20 \%=120 \% \\\\ & 120 \%=\frac{120}{100}=1.2 \\\\ & \$ 30 \times 1.2=\$36 \end{aligned} |
When given two values, you can calculate the percentage difference or percentage change. When the value goes up, this may also be called percent gain, percent profit, or a markup.
You can calculate percent change using the percentage change formula:
\text { Percentage change }=\frac{\text {amount of change }}{\text { original }} \times 100
Percent gain is when the percent increases or gets bigger, between a starting percent and the final percent.
For example,
At the beginning of the month, you had \$50 in your savings account, and by the end of the month, you had \$75. Work out the percent increase.
\text { Percent increase }=\cfrac{75-50}{50} \times 100=50 \%
Percent profit is when a store or person selling a good or a service wants to calculate the difference between the cost price and the selling price and represent it as a percent.
For example,
A school store buys pencils for \$0.80 and sells them to the students for \$1.00. Work out the percent profit.
\text { Percent profit }=\cfrac{1-0.80}{0.80} \times 100=25 \%
Markups are the increased price of a good. A company may markup an item that is in high demand and people are willing to pay more money for it.
For example, if a new makeup item is in high demand, a store may markup the price by a given percent due to the shortage of the item, or overall high demand.
Use this quiz to check your grade 6 to 7 studentsβ understanding of percents. 10+ questions with answers covering a range of 6th and 7th grade percent topics to identify areas of strength and support!
DOWNLOAD FREEUse this quiz to check your grade 6 to 7 studentsβ understanding of percents. 10+ questions with answers covering a range of 6th and 7th grade percent topics to identify areas of strength and support!
DOWNLOAD FREEHow does this relate to 7th grade math?
In order to increase a value by a given percent:
Kalli purchased a collector’s baseball card for \$50 in 2021. In 2022, the value increased by 40\%. What is the value of the baseball card now?
You will first need to solve for 40\% of \$50.
The easiest way is to calculate 10\% (by dividing by 10 ) and then multiply by 4 to get 40\%.
10\% of \$50 = \$5.
5 \times 4=20
40\% of \$50 = \$20.
2Add the calculated percent to the original number.
Add \$20 on to the original value of \$50.
\$ 50+\$ 20=\$ 70
The final answer is \$70.
The value of the baseball card increased to \$70.
Increase 400 by 60\%.
Calculate the given percent of the value.
You will first calculate 60\% of 400.
The easiest way is to calculate 10\% (by dividing by 10 ) and then multiply by 6 to get 60\%.
10\% of 400 = 40.
40 \times 6=240
60\% of 400 = 240.
Add the calculated percent to the original number.
Add 240 on to the original value of 400.
400 + 240 = 640
The final answer is 640.
400 increased by 60\% is 640.
Increase 350 \, m by 30\%.
Calculate the given percent of the value.
You will first calculate 30\% of 350.
The easiest way to calculate 30\% is to calculate 10\% (by dividing by 10 ) and then multiply by 3 to get 30\%.
10\% of 350 = 35.
35 \times 3=105
30\% of 350 = 105.
Add the calculated percent to the original number.
Add 105 \, m on to the original value.
350 \, m+105 \, m=455 \, m
The final answer is 455 \, m.
350 \, m increased by 30\% is 455 \, m.
The price of Katrinaβs train ticket last year was \$75. This year it has increased by 15\%. Find the price of Katrinaβs train ticket this year.
Calculate the given percent of the value.
You will first need to find 15\% of \$75.
10\% of \$75 = \$7.50.
7.50 \div 2=3.75
5\% of \$75 = \$3.75.
\$ 7.50+3.75=\$ 11.25
15\% of \$75 is \$11.25.
Add the calculated percent to the original number.
Add on \$11.25 to the original value.
\$ 75+\$ 11.25=\$ 86.25
The final answer is \$86.25.
Katrinaβs train ticket increased by 15\% is \$86.25.
In order to increase a value by using a percent as a decimal:
Increase 3,200 \, ml by 24\%.
Add the percentage you are increasing by and \bf{100\%} .
Here you are calculating a 24 percent increase, so add 24\% on to 100\%.
100 \%+24 \%=124 \%
Convert the percentage to a decimal.
To do this, you divide the percentage by 100.
124 \% \div 100=1.24
124\% = 1.24
Multiply the original amount by the decimal.
Multiply 3,200 by 1.24.
3,200\times 1.24=3,968 \, ml
The final answer is 3,968 \, ml.
3,200 \, ml increased by 24\% is 3,968 \, ml.
In 2015, Rachelβs monthly rent was \$620. Over the course of five years, Rachelβs monthly rent increased by 12.5\%. Find Rachelβs monthly rent at the end of the five years.
Add the percentage you are increasing by and \bf{100\%} .
This is a 12.5 percent increase, so you add 12.5\% onto 100\%.
100 \%+12.5 \%=112.5 \%
Convert the percentage to a decimal.
112.5 \div 100=1.125
112.5\% = 1.125
Multiply the original amount by the decimal.
Multiply \$620 by 1.125.
620\times 1.125=\$697.50
Remember to always write money using two decimal places.
Rachelβs rent increased from \$620 to \$697.50 over 5 years.
In order to calculate the percent increase after a percent change:
The weight of a lamb has increased from 7 \, kg to 13 \, kg. Find the percent increase in the lambβs weight.
Find the amount of change by subtracting the original number from the new number.
The weight of the lamb has changed from 7 \, kg to 13 \, kg. You will subtract the original weight from the new weight.
13-7=6 \mathrm{~kg}
Plug numbers into the percent change formula.
Apply the percent change formula. The change is 6 \, kg and the original amount is 7 \, kg.
\begin{aligned}
& \text { Percent change }=\cfrac{\text { Change }}{\text { Original }} \times 100 \\\\
& \text { Percent change }=\cfrac{6}{7} \times 100
\end{aligned}
Simplify the fraction, if necessary, using equivalent fractions.
\cfrac{6}{7} \, does not need to be simplified.
\text { Percent change }=\cfrac{6}{7} \times 100
Convert the fraction to a decimal.
\cfrac{6}{7}=85.71
\text{Percent change } =0.86 \times 100
You can round this decimal to 0.86 to solve.
Calculate percent change.
0.86 \times 100=86
\text{Percent change } = 86\%
The lambβs weight has increased by 86\%.
Lucy buys an antique table for \$150 and sells it for \$185. Calculate Lucyβs percent profit.
Find the amount of change by subtracting the original number from the new number.
Work out the change in value by subtracting the original price from the new price:
\$ 185-\$ 150=\$ 35
Plug numbers into the percent change formula.
Apply the percent change formula. The change is \$35 and the original price is \$150.
\text { Percent change }=\cfrac{35}{150} \times 100
Simplify the fraction, if necessary, using equivalent fractions.
\cfrac{35}{150} \, can be simplified to \, \cfrac{7}{30}.
\text { Percent change }=\cfrac{7}{30} \times 100
Convert the fraction to a decimal.
\cfrac{7}{30}=23.333\ldots
\text { Percent change }=0.23 \times 100
This is a repeating decimal, but you can round this decimal to 0.23 to solve.
Calculate percent change.
0.23 \times 100=23
\text{Percent change }=23 \%
Lucyβs percentage profit is 23\%.
Calculate the percent increase that has occurred in each of these questions.
1. Increase \$520 by 20\%.
You will first calculate 20\% of \$520.
10\% of \$520 = \$52.
52 \times 2=104
20\% of \$520 = \$104.
20\% of 520 is 104.
This can be added to the original amount to find the quantity after the increase.
\$ 104+\$ 520=\$ 624
2. Increase 3,400 \, m by 40\%.
You will first calculate 40\% of 3,400.
10\% of 3,400 = 340.
340 \times 4=1,360
40\% of 3,400 = 1,360
40\% of 3,400 is 1,360.
This can be added to the original amount to find the quantity after the increase.
3,400+1,360=4,760
3,400 \, m increased by 40\% is 4,760.
3. Use a percent as a decimal to increase 38 by 14\%.
Add the percentage you are increasing by, 14\%, and 100.
100+14 =114
Next, you will convert the percentage to a decimal by dividing.
114 \div 100=1.14
Then multiply the original amount by the decimal.
38 \times 1.14=43.32
38 increased by 14\% is 43.32.
4. Use a percent as a decimal to increase 650 \, kg by 26\%.
Add the percentage you are increasing by, 26\%, and 100.
100+26 =126
Next, you will convert the percentage to a decimal by dividing.
126 \div 100=1.26
Then multiply the original amount by the decimal.
650 \times 1.26=819
650 \, kg increased by 26\% is 819 \, kg.
5. Find the percent increase when 400 \, ml is increased to 620 \, ml.
First, you will calculate the change from 400 \, ml to 620 \, ml.
620-400=220
The change is 220 \, ml, so you can now plug the numbers into the percent change formula.
\text {Percent change }=\cfrac{220}{400} \times 100
After simplifying the fraction to \, \cfrac{55}{100} \, , you would convert it to the decimal 0.55.
0.55 \times 100=55
\text {Percentage increase }=55 \%
6. Find the percentage profit when Karam buys a house for \$124,000 and sells the house for \$137,640.
First, you will calculate the change from \$124,000 to \$137,640.
137,640-124,000=13,640
The change is \$13,640, so you can now plug the numbers into the percent change formula.
\text {Percent change }=\cfrac{13,640}{124,000} \times 100
After simplifying the fraction to \, \cfrac{11}{100} \, , you would convert it to the decimal 0.11.
0.11 \times 100=11
\text {Percentage increase }=11 \%
If you are finding a percent decrease, or any percentage where the value is decreasing, the initial percent change calculation will result in a negative number. However, you will use the absolute value of the difference to calculate the overall percent change, which will result in a positive number.
It is an automated way for you to calculate the percentage increase of a given value. It is recommended that you use the calculator when dealing with large numbers and decimals.
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