Step-by-step explanation:
well, the first solution that comes to my mind is :
8/4 + 5/1 = 7/1
2 + 5 = 7
the reason : the only numerator I can "cut" into integer pieces is 8.
5 and 7 are prime numbers.
so, it tried to keep 5 and 7 whole, and then add a part of 8 to make this equation true. and that worked right away.
