题目内容
4.下面各题,怎样简便就怎样算.17.8÷(1.78×4)
12.5×3.2×2.5
(3.5-2.8)÷0.7
146.5-(23+46.5)
0.46×55+4.6×4.5
5.6÷3.5.
分析 (1)根据除法的性质简算;
(2)先把3.2分解成8×0.4,再根据乘法结合律简算;
(3)先算小括号里面的减法,再算括号外的除法;
(4)根据减法的性质简算;
(5)先根据积不变规律,把4.6×4.5变成0.46×45,再根据乘法分配律简算;
(6)根据商不变规律简算.
解答 解:(1)17.8÷(1.78×4)
=17.8÷1.78÷4
=10÷4
=2.5
(2)12.5×3.2×2.5
=12.5×(8×0.4)×2.5
=(12.5×8)×(0.4×2.5)
=100×1
=100
(3)(3.5-2.8)÷0.7
=0.7÷0.7
=1
(4)146.5-(23+46.5)
=146.5-46.5-23
=100-23
=77
(5)0.46×55+4.6×4.5
=0.46×55+0.46×45
=0.46×(55+45)
=0.46×100
=46
(6)5.6÷3.5
=(5.6÷7)÷(3.5÷7)
=0.8÷0.5
=1.6
点评 完成本题要注意分析式中数据,运用合适的简便方法计算.
练习册系列答案
相关题目
19.直接写得数.
10.56×10= | 3.15×1000= | 0.101×100= | 12.1÷100= |
7.85÷10= | 3.9÷100= | 0.002×1000= | 0.4÷100= |
10.3÷100= | 2÷1000= | 1.8×10÷100= | 360÷100×10= |