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.