To set up the problem, write 5/12. "Of" in math is the same as writing "×". WN ("What Number") can be used to represent the number you are solving for. "Is" in math is the same as writing "=". At the end, place 7/3.
5/12 × WN = 7/3
Now you have set up your problem.
The next step is to solve. To find WN, solve 7/3 ÷ 5/12.
7/3 is your dividend
5/12 is your divisor
When dividing fractions, divide the dividend by the divisor's reciprocal. (The RECIPROCAL is simply an inverted number. For example, the reciprocal of 4/5 is 5/4 and the reciprocal of 3 is 1/3.) Change the "÷" sign into a "×" sign. Your problem should now look like this:
7/3 × 12/5 =
Now, multiply across. 7 × 12 = 84 AND 3 × 5 = 15
You now have 84/15 as a fraction. When we are finding a missing fraction, we do not turn the fraction into a mixed number. At the end we can. But first, we must reduce the improper fraction to its lowest terms.
The greatest common factor (GCF) of 84 and 15 is 3. So we divide 84 by 3 (28) and 15 by 3 (5). We are left with the improper fraction: 28/5.
Simplified, this would be 5 and 3/5.
So, 3/15 of/× what number/WN is/= 7/3 is: 28/5 OR 5 3/5