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3.29-(1数学公式+1.29)
2700-780÷26×34
1.25×32×2.5
数学公式×45-数学公式÷数学公式

解:(1)3.29-(1+1.29),
=3.29-1.29-1
=2-1
=

(2)2700-780÷26×34,
=2700-30×34,
=2700-1020,
=1680;

(3)1.25×32×2.5,
=1.25×8×4×2.5,
=(1.25×8)×(4×2.5),
=10×10,
=100;

(4)×45-÷
=×45-×45,
=(-)×45,
=0×45,
=0.
分析:(1)根据减去两个数的和等于连续减去两个数简算;
(2)先算除法,再算除法,最后算减法;
(3)先把32分解成8×4,再使用乘法结合律简算;
(4)先把除法变成乘法,再运用乘法分配律简算.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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