问题 解答题
怎样简便怎样计算:
(1)31.2×91+3.12×90(2)0.25×3.2×12.5(3)2.95×101-2.95
(4)89×100.1(5)99÷0.25÷0.4(6)35.6-6×1.73.
答案

(1)31.2×91+3.12×90,

=31.2×91+31.2×9,

=31.2×(91+9),

=31.2×100,

=3120;

(2)0.25×3.2×12.5,

=0.25×8×0.4×12.5,

=(0.25×0.4)×(8×12.5),

=0.1×100,

=10;

(3)2.95×101-2.95,

=2.95×(101-1),

=2.95×100,

=295;

(4)89×100.1,

=89×(100+0.1),

=89×100+89×0.1,

=8900+8.9,

=8908.9;

(5)99÷0.25÷0.4,

=99÷(0.25×0.4),

=99÷0.1,

=990;

(6)35.6-6×1.73,

=35.6-10.38,

=25.22.

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