What is the missing number.

5 / 6 = ?/18

15

Step-by-step explanation:

So, we know that 5/6 is equal to something over 18. The denominator of 5/6 is a factor of 18, which makes it easy to find the missing numerator. 6 goes into 18 three times, so let's multiply 5 by 3. We get 15. 5/6=15/18, so your missing number is 15.