1)5/12 - 2/9 = 45/108 - 24/108 = 21/108
2)1/8 + 7/12 = 12/96 + 56/96 = 68/96
3) 3/4 - 1/6 = 18/24 - 4/24 = 14/24
1) 5/12-2/9=(5×3-2×4)/36=(15-8)/36=7/36;
2) 1/8+7/12=(1×3+7×2)/24=(3+14)/24=17/24;
3) 3/4-1/6=(3×3-1×2)/12=(9-2)/12=7/12.
