题目内容
计算下面各题,能简算的要简算.(要写计算过程)
173+428+72 | 3196-(196+310) | 72×102-2×72 | 125×25×32. |
解:(1)173+428+72,
=173+(428+72),
=173+500,
=673;
(2)3196-(196+310),
=3196-196-310,
=3000-310,
=2690;
(3)72×102-2×72,
=(102-2)×72,
=100×72,
=7200;
(4)125×25×32,
=125×25×8×4,
=(125×8)×(25×4),
=1000×100,
=100000.
分析:(1)运用加法结合律简算;
(2)根据减法的性质简算;
(3)运用乘法分配律简算;
(4)先把32分解成8×4,再运用乘法结合律简算.
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.
=173+(428+72),
=173+500,
=673;
(2)3196-(196+310),
=3196-196-310,
=3000-310,
=2690;
(3)72×102-2×72,
=(102-2)×72,
=100×72,
=7200;
(4)125×25×32,
=125×25×8×4,
=(125×8)×(25×4),
=1000×100,
=100000.
分析:(1)运用加法结合律简算;
(2)根据减法的性质简算;
(3)运用乘法分配律简算;
(4)先把32分解成8×4,再运用乘法结合律简算.
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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