题目内容
÷[] | ÷23+× |
×5.7+5.9×7.5-1.6× | 8.15-2.93-1.07-3.15 |
解:
(1)÷[],
=÷[÷],
=÷,
=;
(2)÷23+×,
=×+×,
=(+)×,
=1×,
=;
(3)×5.7+5.9×7.5-1.6×,
=7.5×5.7+5.9×7.5-1.6×7.5,
=7.5×(5.7+5.9-1.6),
=7.5×10,
=75;
(4)8.15-2.93-1.07-3.15,
=(8.15-3.15)-(2.93+1.07),
=5-4,
=1.
分析:(1)先算小括号里面的加法,再算中括号里面的除法,最后算中括号外面的除法;
(2)根据乘法分配律进行计算;
(3)根据乘法分配律进行计算;
(4)根据加法交换律及减法的性质进行计算.
点评:四则混合运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.
(1)÷[],
=÷[÷],
=÷,
=;
(2)÷23+×,
=×+×,
=(+)×,
=1×,
=;
(3)×5.7+5.9×7.5-1.6×,
=7.5×5.7+5.9×7.5-1.6×7.5,
=7.5×(5.7+5.9-1.6),
=7.5×10,
=75;
(4)8.15-2.93-1.07-3.15,
=(8.15-3.15)-(2.93+1.07),
=5-4,
=1.
分析:(1)先算小括号里面的加法,再算中括号里面的除法,最后算中括号外面的除法;
(2)根据乘法分配律进行计算;
(3)根据乘法分配律进行计算;
(4)根据加法交换律及减法的性质进行计算.
点评:四则混合运算,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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