| 10.4+0.6×0.8 | (18.7+1.3)×1.4 | 1.5×2.06-0.06 |
| 1.7×4.9+4.9×8.3 | 39.6-9.6÷3 | 1.2×103 |
(1)10.4+0.6×0.8,
=10.4+0.48,
=10.88;
(2)(18.7+1.3)×1.4,
=20×1.4,
=28;
(3)1.5×2.06-0.06,
=3.09-0.06,
=3.03;
(4)1.7×4.9+4.9×8.3,
=(1.7+8.3)×4.9,
=10×4.9,
=49;
(5)39.6-9.6÷3,
=39.6-3.2,
=36.4;
(6)1.2×103,
=1.2×(100+3),
=1.2×100+1.2×3,
=120+3.6,
=123.6.
分析:(1)先算乘法,再算加法;
(2)先算加法,再算乘法;
(3)先算乘法,再算减法;
(4)根据乘法分配律进行简算;
(5)先算除法,再算减法;
(6)根据乘法分配律进行简算.
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.