1/4+2/9-5/36= 3/4+4/5+1/20= 3/4+5/12-1/9= 4/15+2/5+7/10=

1/4+2/9-5/36= (9+8-5)/36=12/36=1/3

3/4+4/5+1/20=(20+16+1)/20=37/20=1 17/20

3/4+5/12-1/9= (27+15-4)/36=38/36=1 2/36=1 1/18

4/15+2/5+7/10=(8+12+21)/30=41/30=1 11/30