怎样简便就怎样计算:2.9×1.4+2×0.16    5.4×2.08+66×0.208-2.0830.8÷[14-(
2个回答

解题思路:(1)、(3)据四则混合运算法则计算即可;

(2)可将式中66×0.208变为6.6×2.08后据分配律进行简算;

(4)式中(12.5+1.25+0.125)×80可据分配律进行简算.

(1)2.9×1.4+2×0.16

=4.06+0.32,

=4.38;

(2)5.4×2.08+66×0.208-2.08

=5.4×2.08+6.6×2.08-2.08,

=(5.4+6.6-1)×2.08,

=11×2.08,

=22.88;

(3)30.8÷[14-(9.85+1.07)]

=30.8÷[14-10.92]

=30.8÷3.08,

=10;

(4)[(12.5+1.25+0.125)×80-999]÷0.03

=[(12.5×80+1.25×80+0.125×80)-999]÷0.03,

=[(1000+100+10)-999]÷0.03,

=[1110-999]÷0.03,

=111÷0.03,

=3700.

点评:

本题考点: 运算定律与简便运算;小数四则混合运算.

考点点评: 解答本题要注意分析式中数据,找到合适的简算方法.