To answer this specific problem, the measure of ∡DEF
is 64. I am hoping that this answer has satisfied your query and it will
be able to help you in your endeavor, and if you would like, feel free to ask
another question.
The answer is......... 27
Answer: 
This is the same as writing (n-m)/n
Don't forget about the parenthesis if you go with the second option.
==================================================
Explanation:
The probability that she wins is m/n, where m,n are placeholders for positive whole numbers.
For instance, m = 2 and n = 5 leads to m/n = 2/5. This would mean that out of n = 5 chances, she wins m = 2 times.
The probability of her not winning is 1 - (m/n). We subtract the probability of winning from 1 to get the probability of losing.
We could leave the answer like this, but your teacher says that the answer must be "in the form of a combined single fraction".
Doing a bit of algebra would have these steps

and now the expression is one single fraction.
Answer= 1,3,5,15
which are in essence all on the factors of 15