G=3/2 -1/5x25/7
=3/2-25/35
=3/2-5/7
=21/14-10/14
=11/14
H=(2/8 - 3/15) :3/10
=(1/4-3/15)*10/3
=(15/60-12/60)*10/3
=3/60*10/3
=10/60
=1/6
I= 5/4 +2/5
---------------
2 -7/5
=(5/4+2/5)/(2-7/5)
=(25/20+8/20)/(10/5-7/5)
=(33/20)/(3/5)
=33/20*5/3
=(11*5)/20
=11/4