Percents of numbers and money amounts
Key notes:
A percent is 1 part out of 100.
1% is equal to 1/100 or 0.01
Proportions can be used to solve percent problems.
part / whole = percent / 100
Learn with an example
🔔 What is 10% of 90?
The whole is 90.
The percent is 10%.
Let n represent the part.
Write a proportion to solve for n.
n / 90 = 10 / 100
100n = 10 · 90
100n = 900
100n ÷ 100 = 900 ÷ 100
n = 9
10% of 90 is 9.
You could also find the answer by writing and solving an equation:
part = percentage of whole
n = 10% · 90
n = 0.1 · 90
n = 9
10% of 90 is 9.
🔔 Fill in the missing number.
100% of 59 = _____
100% of a number is the entire number. 100% of 59 is 59. You can check this by doing the maths.
The whole is 59.
The percent is 100%.
Let n represent the part.
Write a proportion to solve for n.
n/59 = 100/100
100n = 100 · 59
100n = 5,900
100n ÷ 100 = 5,900 ÷ 100
n = 59
100% of 59 = 59
You could also find the answer by writing and solving an equation:
part = percentage of whole
n = 100% · 59
n = 1 · 59
n = 59
100% of 59 = 59
🔔 Fill in the missing number.
80% of 40 =____
The whole is 40.
The percent is 80%.
Let n represent the part.
Write a proportion to solve for n.
n/40 = 80/100
100n = 80 · 40
100n = 3,200
100n ÷ 100 = 3,200 ÷ 100
n = 32
80% of 40 = 32
You could also find the answer by writing and solving an equation:
part = percentage of whole
n = 80% · 40
n = 0.8 · 40
n = 32
80% of 40 = 32
Let’s practice! 🖊️
