(2014•雁江区模拟)怎么简便就怎么算.

1个回答

  • 解题思路:①先算除法,再算乘法,最后算加法;

    ②根据乘法分配律进行简算;

    ③根据乘法分配律进行简算;

    ④根据乘法分配律进行简算;

    ⑤先算乘法,再算减法,最后算除法;

    ⑥中括号里面的根据减法的性质进行简算,最后算乘法.

    ①375+450÷18×25

    =375+25×25

    =375+625

    =1000;

    ②4.6×0.25-[3/5]÷4

    =4.6×0.25-[3/5]×0.25

    =(4.6-[3/5])×0.25

    =4×0.25

    =1;

    ③4.2×1.85+4.2×7.15+4.2

    =4.2×(1.85+7.15+1)

    =4.2×10

    =42;

    ④[5/9]×[3/4]+[5/9]×[3/4]

    =([5/9]+[5/9])×[3/4]

    =[10/9]×[3/4]

    =[5/6];

    ⑤(7.5×1.08-5.37)÷0.35

    =(8.1-5.37)÷0.35

    =2.73÷0.35

    =7.8;

    ⑥[8/9]×[0.75-([7/16]-[1/4])]

    =[8/9]×[0.75-[7/16]+[1/4]]

    =[8/9]×[0.75+[1/4]-[7/16]]

    =[8/9]×[1-[7/16]]

    =[8/9]×[9/16]

    =[1/2].

    点评:

    本题考点: 分数的四则混合运算;运算定律与简便运算;小数四则混合运算.

    考点点评: 考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.