Question

用简便方法计算．
①3.5%×9.9                   
②4.62+9.9
③7.25×1.8+27.5×0.18．

Answer 1

考点：运算定律与简便运算

专题：运算定律及简算

分析：①把9.9分成10-0.1，然后根据乘法分配律解答即可．
②把9.9分成10-0.1，然后根据加法结合律计算即可．
③根据乘法分配律解答即可．

解答： 解：①3.5%×9.9
=0.035×（10-0.1）
=0.035×10-0.035×1
=0.35-0.035
=0.315                   

②4.62+9.9
=4.62+10-0.1
=14.62-0.1
=14.52

③7.25×1.8+27.5×0.18
=7.25×1.8+2.75×1.8
=（7.25+2.75）×1.8
=10×1.8
=18

点评：此题主要考查了加法、乘法运算定律的运用．