I whole and 3 over 4 minus 7 over 8?

Answer 1

The trick here - apart from the usual one, of finding a common denominator - is to "lend" one from the whole part, and add it to the fraction. Since one whole is 3/4, you add 4/4, to get 7/4. Then (and after converting everything to the common denominator), you can easily subtract the fractional part.

Answer 2

14/8 - 7/8 = 7/8