If you are rewriting 15/9, then you have to convert it to a mixed number. The fraction 15/9 is an improper fraction.
To covert the improper fraction to a mixed number, so the steps below.
Divide the numerator by the denominator since the numerator is greater than the denominator (15> 9).
When you divide 15÷9, then you figure out that 9 goes to 15 only one time (since 9x1=9, however, if you do 9x2=18).
Next subtract the product (9 ) from 15. The difference is 6 (15-9=6).
The 1 will be the whole number, however, the remainder (which is 6), will be the fraction. It's not done yet. The 6 is the numerator and the denominator will be the 9. So the mixed number is 1 6/9. However, you can simplify the 6/9 after dividing both the numerator and the denominator by 3. So 6÷3=2 and 9÷3=3. The final answer will then be 1 2/3.