1/5+1/2=2/10+5/10=7/10
3/4+1/2=3/4+2/4=5/4=1 1/4
1/6+1/2=1/6+3/6=4/6=2/3
4/5+2/3=12/15+10/15=22/15=1 7/17
2/3+3/4=8/12+9/12=17/12=1 5/12
