题目内容
递等式计算,能简便的用简便方法计算
5.41+3.46-2.46 | 2.03-0.18-2.82+7.97 | 10-4.44-5.56 |
32.63+7.89-6.4 | 125×25×32 | 97×88. |
解:
(1)5.41+3.46-2.46,
=5.41+(3.46-2.46),
=5.41+1,
=6.41;
(2)2.03-0.18-2.82+7.97,
=(2.03+7.97)-(0.18+2.82),
=10-3,
=7;
(3)10-4.44-5.56,
=10-(4.44+5.56),
=10-10,
=0;
(4)32.63+7.89-6.4,
=40.52-6.4,
=34.12;
(5)125×25×32,
=125×25×(8×4),
=(125×8)×(25×4),
=1000×100,
=100000;
(6)97×88,
=(100-3)×88,
=100×88-3×88,
=8800-264,
=8536.
分析:(1)根据加法结合律进行计算;
(2)根据加法交换律和结合律以及连减的性质进行计算;
(3)根据连减的性质进行计算;
(4)先算加法,再算减法;
(5)根据乘法交换律和结合律进行计算;
(6)根据乘法分配律进行计算.
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.
(1)5.41+3.46-2.46,
=5.41+(3.46-2.46),
=5.41+1,
=6.41;
(2)2.03-0.18-2.82+7.97,
=(2.03+7.97)-(0.18+2.82),
=10-3,
=7;
(3)10-4.44-5.56,
=10-(4.44+5.56),
=10-10,
=0;
(4)32.63+7.89-6.4,
=40.52-6.4,
=34.12;
(5)125×25×32,
=125×25×(8×4),
=(125×8)×(25×4),
=1000×100,
=100000;
(6)97×88,
=(100-3)×88,
=100×88-3×88,
=8800-264,
=8536.
分析:(1)根据加法结合律进行计算;
(2)根据加法交换律和结合律以及连减的性质进行计算;
(3)根据连减的性质进行计算;
(4)先算加法,再算减法;
(5)根据乘法交换律和结合律进行计算;
(6)根据乘法分配律进行计算.
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.
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