问题 解答题

下面各题,能简算的要用简便方法计算.

3.9+0.56+6.1+0.44

50÷2.5+1.8×4.5

6.87×[40÷(3.49-3.09)]

0.8×(12.5+0.125)

答案

(1)3.9+0.56+6.1+0.44,

=(3.9+6.1)+(0.56+0.44),

=10+1,

=11;

(2)50÷2.5+1.8×4.5,

=20+8.1,

=28.1;

(3)6.87×[40÷(3.49-3.09)],

=6.87×[40÷0.4],

=6.87×100,

=687;

(4)0.8×(12.5+0.125),

=0.8×12.5+0.8×0.125,

=10+0.1,

=10.1.

解答题
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