How do i turn mix numbers into improper fraction

You multiply the whole number and the denominator ( the bottom number in the fraction) and then add the answer of that to the numerator. Hope that helps! :) 

Ok, lets do an example of how to do one.  Lets say you have:

3 12/15.
12 is your numerator and 15 is your denominator (numerator is the number on top, denominator is the number on bottom). If it takes 15/15 pieces to make the number 1, then for the number three, there must be 15 parts for every 1 in the number three, so:

1= 15/15.
           15 15 15
1+1+1= ---+--+---
           15 15 15
so to make 3 12/15 into a improper fraction we must do:

15 15 15 12
---+--+---+---=?
15 15 15 15

remember when adding fractions, you only add the numerators, so:

15 15 15 12  57
---+--+---+---= ---
15 15 15 15  15

57
---   would be your improper fraction.
15

If you need me to explain anything else or you just simply have any questions, feel free to ask me below. Also please mark this answer as the brainliest if it wouldn't be any trouble :).