题目内容
18.下列各题,能简便的要简算.3.8+9.4-5.6 | 0.124+3.75+4.876+6.25 | 27.38-5.34+2.62-4.66 |
16.55-(6.55-3.7) | 1.3×0.25+0.25×0.7 | 6.8×101-6.8 |
分析 (1)按照从左到右的顺序计算;
(2)根据加法交换律和结合律简算;
(3)根据加法交换律和结合律,以及减法的性质简算;
(4)先去括号,再计算;
(5)根据乘法分配律简算;
(6)根据乘法分配律简算.
解答 解:(1)3.8+9.4-5.6
=13.2-5.6
=7.6
(2)0.124+3.75+4.876+6.25
=(0.124+4.876)+(3.75+6.25)
=5+10
=15
(3)27.38-5.34+2.62-4.66
=(27.38+2.62)-(5.34+4.66)
=30-10
=20
(4)16.55-(6.55-3.7)
=16.55-6.55+3.7
=10+3.7
=13.7
(5)1.3×0.25+0.25×0.7
=(1.3+0.7)×0.25
=2×0.25
=0.5
(6)6.8×101-6.8
=6.8×(101-1)
=6.8×100
=680
点评 本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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