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Use these tips below to quickly calculate percentages like tip, all without a calculator!

Multiply Whole Numbers

First, always multiply using whole numbers since this is the easiest to do in your head.

Move the decimal over

Percentages represent a number out of 100, so first multiply the whole numbers, then move the decimal point over. Example: 30% (or 30/100) of 90 can be found by multiplying 30 x 90 = 2700. Then, move the decimal place back two places to the left to get the answer 27.

Approximations

If an exact number isn’t needed, you can always round to the closest multiple for a quick approximation. Example: 40% of 72 can be estimated by multiplying 40x70 = 2800 –> move the decimal over two places –> 28

More Advanced

For harder to multiply percentages (such as 15%, 25%, etc), it is often easier to find another percentage and then manipulate it to get your final number. Here are some common percentages and how to calculate them:

5% = 10% divided by 2
15% = 10% + half of 10%
20% = 10% x 2
25% = 50% divided by 2
60% = 50% + 20%
75% = 50% + 25%

Example: 60% of 200 is equivalent to 100 (50%) + 20 (10%) = 120

Now go on and impress your friends calculating tip the next time your dinner bill arrives!