问题 解答题

用简便方法计算

(1)56×12.5

(2)14.6-(4.6+7.2)

(3)99×99+199.

答案

(1)56×12.5,

=7×(8×12.5),

=7×100,

=700;

(2)14.6-(4.6+7.2),

=14.6-4.6-7.2,

=10-7.2,

=2.8;

(3)99×99+199,

=99×99+99+100,

=99×(99+1)+100,

=99×100+100,

=9900+100,

=10000.

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