To find the whole number by its fraction, we divide the number by the numerator of the fraction and multiply the result by the denominator of the fraction.
For example, knowing that 
of the tape measure is 12 cm, we can find the length of the entire tape measure. To do this, divide 12 by 2, and multiply the result by 3.
12 : 2 = 6
6 × 3 = 18
We got 18. So the length of the whole tape measure is 18 cm.
But there is a second version of the solution. To find the length of the whole tape measure, just divide 12 by a fraction of . Then we get the same result as last time, but we get it in one step:
Therefore, you may want to take note of the following rule for finding a number by a fraction:
To find a number by a fraction, divide the number by the fraction.
Example 2. 
of the whole path is 6 km. Find the length of the entire path.
To find the length of the entire path, simply divide 6 by the fraction .
The answer is 15. So the length of the entire path is 15 kilometers.
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