题目内容
7.脱式计算(能简算的要简算)7.69×101 0.25×39+0.25 8.57+5.68-3.68
6.13-2.98+0.89 12.58-0.72-0.28 2.3×98+4.6.
分析 (1)根据乘法分配律简算即可;
(2)运用乘法分配律简算;
(3)运用加法结合律简算;
(4)从左往右依次计算;
(5)运用减法的性质简算;
(6)把4.6看作2.3×2,运用乘法分配律简算.
解答 解:(1)7.69×101
=7.69×100+7.69×1
=769+7.69
=776.69
(2)0.25×39+0.25
=0.25×(39+1)
=0.25×40
=10
(3)8.57+5.68-3.68
=8.57+(5.68-3.68)
=8.57+2
=10.57
(4)6.13-2.98+0.89
=3.15+0.89
=4.04
(5)12.58-0.72-0.28
=12.58-(0.72+0.28)
=12.58-1
=11.58
(6)2.3×98+4.6
=2.3×98+2.3×2
=2.3×(98+2)
=2.3×100
=230
点评 此题考查了小数的四则混合运算,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.
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