Question

what number should be subtracted from3/7 to get 5/4

Answer 1

let the number subtracted=x
now,3/7-5/4
=12-35/28
=-23/28

Answer 2

x - 3/7 = 5/4
x = 5/4 +3/7
x = (35+12)/28
x = 47/28

to check whether 47/28 correct or not:

47/28 - 3/7 = 5/4
(47-12)/28 = 5/4
35/28 = 5/4
5/4 = 5/4
both sides are equal so 47/28 is correct