Firstly you know that 7-3 is 4 so that is your whole number. next fro the fractions you have to create a common denominator.In this case both denominators can be. so 1 times 2 is 2 and 4 times 2 is 8.so 7/8 minus 2/8 is 5/8. your answer will be 4 and 5/8