怎样简便就怎么样算.
4.8+2.71+5.2+5.29
35×69+65×69
4×27×25
31.29-3.87-6.13.
解:(1)4.8+2.71+5.2+5.29,
=(4.8+5.2)+(5.29+2.71),
=10+8,
=18;
(2)35×69+65×69,
=(35+65)×69,
=100×69,
=6900;
(3)4×27×25,
=4×25×27,
=100×27,
=2700;
(4)31.29-3.87-6.13,
=31.29-(3.87+6.13),
=31.29-10,
=21.29.
分析:(1)运用加法交换律和加法结合律简算;
(2)运用乘法分配律简算;
(3)运用乘法交换律简算;
(4)根据连续减去两个数,等于减去这两个数的和简算.
点评:本题考查了基本的运算,要注意分析数据,选择合适的简算方法计算.