题目内容

4.用递等式计算,能简便的要简便:
2.5×(12.3×0.4)5.9+2.5÷25             3.56×7.8+3.56×2.2
2.6÷0.13-19.9              12÷0.125÷8              0.02×(21.7÷0.7)

分析 (1)根据乘法交换律和结合律进行简算;
(2)先算除法,再算加法;
(3)根据乘法分配律进行简算;
(4)先算除法,再算减法;
(5)根据除法的性质进行简算;
(6)先算除法,再算乘法.

解答 解:(1)2.5×(12.3×0.4)
=12.3×(2.5×0.4)
=12.3×1
=12.3;

(2)5.9+2.5÷25
=5.9+0.1
=6;

(3)3.56×7.8+3.56×2.2
=3.56×(7.8+2.2)
=3.56×10
=35.6;

(4)2.6÷0.13-19.9
=20-19.9
=0.1;

(5)12÷0.125÷8
=12÷(0.125×8)
=12÷1
=12;

(6)0.02×(21.7÷0.7)
=0.02×31
=0.62.

点评 考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.

练习册系列答案
相关题目

违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com

精英家教网