【题目】
用简便方法计算.
6.2+5.18+2.8
15.35-(5.35+7.2)
3.63-1.25+17.37-8.75
13.7-9.9
98×45+2×45
56×102.
分析:(1)运用加法交换律解答,
(2)(4)运用减法性质解答,
(3)运用加法交换律和减法性质解答,
(5)(6)运用乘法分配律解答.解答:解:(1)6.2+5.18+2.8,
=6.2+2.8+5.18,
=9+5.18,
=14.18;
(2)15.35-(5.35+7.2),
=15.35-5.34-7.2,
=10-7.2,
=2.8;
(3)3.63-1.25+17.37-8.75,
=(3.63+17.37)-(1.25+8.75),
=21-10,
=11;
(4)13.7-9.9,
=13.7-10+0.1,
=3.7+0.1,
=3.8;
(5)98×45+2×45,
=45×(98+2),
=45×100,
=4500;
(6)56×102,
=56×100+56×2,
=5600+112,
=5712.点评:本题考查知识点:正确运用简便算法解决问题.