题目内容
能用简便方法的用简便方法计算:
25×32×1.25 | 5.4×58+42×5.4 | 6.25÷(0.25×4) |
分析:(1)先把32分解成4×8,再运用乘法结合律简算;
(2)运用乘法分配律简算;
(3)先算小括号里面的乘法,再算括号外的除法.
(2)运用乘法分配律简算;
(3)先算小括号里面的乘法,再算括号外的除法.
解答:解:(1)25×32×1.25,
=25×4×8×1.25,
=(25×4)×(8×1.25),
=100×10,
=1000;
(2)5.4×58+42×5.4,
=5.4×(58+42),
=5.4×100,
=540;
(3)6.25÷(0.25×4),
=6.25÷1,
=6.25.
=25×4×8×1.25,
=(25×4)×(8×1.25),
=100×10,
=1000;
(2)5.4×58+42×5.4,
=5.4×(58+42),
=5.4×100,
=540;
(3)6.25÷(0.25×4),
=6.25÷1,
=6.25.
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.
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