题目内容
递等式计算(能简算的要简算).
(1)92.3-55.51+4.49
(2)6.52+1.43+8.57+3.48
(3)75.8-13.57-1.43
(4)39×89+39×12-39
(5)5208÷(31×56)
(6)(2657+35×26)÷29.
(1)92.3-55.51+4.49
(2)6.52+1.43+8.57+3.48
(3)75.8-13.57-1.43
(4)39×89+39×12-39
(5)5208÷(31×56)
(6)(2657+35×26)÷29.
分析:(1)按从左到右的顺序计算即可;
(2)可根据加法交换律计结合律计算;
(3)可根据一个数减两个数,等于用这个数减去两个数的和的减法性质计算;
(4)可根据乘法分配律计算;
(5)(6)根据四则混合运算的运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号里面的.
(2)可根据加法交换律计结合律计算;
(3)可根据一个数减两个数,等于用这个数减去两个数的和的减法性质计算;
(4)可根据乘法分配律计算;
(5)(6)根据四则混合运算的运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号里面的.
解答:解:(1)92.3-55.51+4.49
=36.79-4.49,
=32.3;
(2)6.52+1.43+8.57+3.48
=(6.52+3.48)+(1.43+8.57),
=10+10,
=20;
(3)75.8-13.57-1.43
=75.8-(13.57+1.43),
=75.8-15,
=60.8;
(4)39×89+39×12-39
=(89+12-1)×39,
=100×39,
=3900;
(5)5208÷(31×56)
=5208÷1736,
=3;
(6)(2657+35×26)÷29
=(2657+910)÷29,
=3567÷29,
=123.
=36.79-4.49,
=32.3;
(2)6.52+1.43+8.57+3.48
=(6.52+3.48)+(1.43+8.57),
=10+10,
=20;
(3)75.8-13.57-1.43
=75.8-(13.57+1.43),
=75.8-15,
=60.8;
(4)39×89+39×12-39
=(89+12-1)×39,
=100×39,
=3900;
(5)5208÷(31×56)
=5208÷1736,
=3;
(6)(2657+35×26)÷29
=(2657+910)÷29,
=3567÷29,
=123.
点评:在利用递等式计算时,要注意计算过程的完整性,中间不要有太大跳跃.
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