问题 解答题
用简便方法计算.
86×137+8690.02-20.06-19.9471×99.
答案

(1)86×137+86,

=86×(137+1),

=86×138,

=11868;

(2)90.02-20.06-19.94,

=90.02-(20.06+19.94),

=90.02-40,

=50.02;

(3)71×99,

=71×(100-1),

=71×100-71×1,

=7100-71,

=7029.

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