运用乘法的运算定律计算下面各题.
来源:学生作业帮 编辑:灵鹊做题网作业帮 分类:数学作业 时间:2024/05/11 14:41:51
运用乘法的运算定律计算下面各题. (125-40)×8 | 57×15+23×15 |
125×32-125×24 | 45×102 |
25×44 | 81+9×81. |
(1)(125-40)×8,
=125×8-40×8,
=1000-320,
=680;
(2)57×15+23×15,
=(57+23)×15,
=80×15,
=1200;
(3)125×32-125×24,
=125×(32-24),
=125×8,
=1000;
(4)45×102,
=45×(100+2),
=45×100+45×2,
=4500+90,
=4590;
(5)25×44,
=25×4×11,
=100×11,
=1100;
(6)81+9×81,
=81×1+9×81,
=81×(1+9),
=81×10,
=810.
=125×8-40×8,
=1000-320,
=680;
(2)57×15+23×15,
=(57+23)×15,
=80×15,
=1200;
(3)125×32-125×24,
=125×(32-24),
=125×8,
=1000;
(4)45×102,
=45×(100+2),
=45×100+45×2,
=4500+90,
=4590;
(5)25×44,
=25×4×11,
=100×11,
=1100;
(6)81+9×81,
=81×1+9×81,
=81×(1+9),
=81×10,
=810.