题目内容
脱式计算(能简算的要简算) (1)4.65-1.55-1.45 | (2)58.1-29.7÷3 |
(3)201×3.5-3.5 | (4)2.2×0.25+0.25×1.8. |
解:(1)4.65-1.55-1.45,
=4.65-(1.55+1.45),
=4.65-3,
=1.65;
(2)58.1-29.7÷3,
=58.1-9.9,
=58.1-(10-0.1),
=58.1-10+0.1,
=48.2;
(3)201×3.5-3.5,
=(201-1)×3.5,
=200×3.5,
=700;
(4)2.2×0.25+0.25×1.8,
=(2.2+1.8)×0.25,
=4×0.25,
=1.
分析:(1)运用减法的性质简算;
(2)先算出发,再算剑法;
(3)(4)运用乘法分配律简算.
点评: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简算.
=4.65-(1.55+1.45),
=4.65-3,
=1.65;
(2)58.1-29.7÷3,
=58.1-9.9,
=58.1-(10-0.1),
=58.1-10+0.1,
=48.2;
(3)201×3.5-3.5,
=(201-1)×3.5,
=200×3.5,
=700;
(4)2.2×0.25+0.25×1.8,
=(2.2+1.8)×0.25,
=4×0.25,
=1.
分析:(1)运用减法的性质简算;
(2)先算出发,再算剑法;
(3)(4)运用乘法分配律简算.
点评: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简算.
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