# Percent of a number

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##### Intros
###### Lessons
• What is a percent?
• How to find the percent of a number?
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##### Examples
###### Lessons
1. Evaluate without using a calculator. Then, check your answers with a calculator.
1. 15% of 40
2. 320% of 600
3. 17.5% of 20
4. $20\frac{1}{4}$% of 50
2. The total rain precipitation of last summer was 350 mm. If it increased by $12\frac{1}{2}$% this summer, what was the rain precipitation this summer?
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##### Practice
###### Topic Notes
In this section, we will try to estimate the percent of a number without using a calculator. The trick is to breakdown the percent into smaller percent first. These smaller percentages are easier for mental calculation.