试题与答案

用简便方法计算下面各题. 0.125×5.46×8 2.5×3.2×125 4.

题型:解答题

题目:

用简便方法计算下面各题.

0.125×5.46×8

2.5×3.2×125

4.9×101

4.5×12.6-3.6×4.5+4.5

5.74×99+5.74

19.7×lOl-19.7.

答案:

(1)0.125×5.46×8,

=(0.125×8)×5.46,

=1×5.46,

=5.46;

(2)2.5×3.2×125,

=(2.5×4)×(0.8×125),

=10×100,

=1000;

(3)4.9×101,

=4.9×100+4.9×1,

=490+4.9,

=494.9;

(4)4.5×12.6-3.6×4.5+4.5,

=4.5×(12.6-3.6+1),

=4.5×10,

=45;

(5)5.74×99+5.74,

=5.74×(99+1),

=5.74×100,

=574;

(6)19.7×lOl一19.7.

=19.7×(101-1),

=19.7×100,

=1970.

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