To find a fraction of a number, we divide the number by the denominator of the fraction and multiply the result by the numerator of the fraction.
For example, to find 
of 10 centimeters, you need to divide 10 by 5, and multiply the result by 2.
10 : 5 = 2
2 × 2 = 4
The answer is 4. So of ten centimeters is 4 centimeters. Schematically it looks like this:
To find of ten centimeters, just multiply 10 by . Then we get the same result as last time, but we get it in one step:
Therefore, we can take note of the following rule for finding a fraction of a number:
To find a fraction of a number, multiply the number by the fraction you are looking for.
Example 2. Find 
of two hours.
Two hours is 120 minutes. To find of 120 minutes, multiply 120 by a fraction of
So of two hours is 80 minutes.
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