First, Find the common denominator of 4 and 7 which is 28. 28 will be the denominator of your difference.Then, now time to multiply, now you multiply 7 by 21 because you multiplied 7 by 4 to get 28. You do the same for the others one but a bit different because this time you multiply 4 by 3= 12 now you have 21/28 and 12/28. Now you add 21 and 12 not 28 because you don't multiply denominators in this case. After that you get 33/28, this is an improper fraction so you divide. 28 goes into 33 once so you have a whole number 1 then you have 5 left over making it the numerator. Result 1 5/28, because you have the whole number 2 left from the equation you add it ending up with 3 5/8
