(2008•高邮市)脱式计算:(1)(3.8-1.8÷2)×0.5(2)[1/2]+[9/20÷910]-[5/8](3
1个回答

解题思路:本题根据四则混合运算的运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号里面的.

(1)(3.8-1.8÷2)×0.5,

=(3.8-0.9)×0.5,

=2.9×0.5,

=1.45;

(2)[1/2]+[9/20÷

9

10]-[5/8],

=[1/2]+[9/20×

10

9]-[5/8],

=[1/2]+[1/2]-[5/8],

=1-[5/8],

=[3/8];

(3)[9/10]÷[[1/2]×([6/5×

3

10])],

=[9/10]÷[[1/2]×[9/25]],

=[9/10]÷

9

50,

=[9/10×

50

9],

=5.

点评:

本题考点: 小数四则混合运算;分数的四则混合运算.

考点点评: 当算式中同时含有中括号与小括号时,要先算小括号里面的,再算中括号里面的.