运用乘法的运算定律计算下面各题。 (1)(125-40)×8 (2)57×15+23×15 (3)125×32-125×24 (4)88×102 (5)125×88 (6)81+9×91
(1)原式=125×8-40×8 =1000-320 =680 | (2)原式=(57+23)×15 =80×15 =1200 |
(3)原式=125×(32-24) =1000 | (4)原式=88×(100+2) =8976 |
(5)原式=125×8×11 =1000×11 =11000 | (6)原式=9×9+9×91 =9×(9+91) =900 |