(2012•屯留县模拟) 57.5-4.25-15.75

1个回答

  • 解题思路:(1)连续减去两个数,就等于减去这两个数的和;

    (2)把32拆成8×4,然后再计算即可;

    (3)根据乘法分配律进行计算即可;

    (4)把99拆成98+1,再根据乘法分配律进行计算即可;

    (5)把[1/4]化成0.25,再根据乘法分配律进行计算即可;

    (6)80%化成0.8,[4/5]化成0.8,再根据乘法分配律进行计算即可.

    (1)57.5-4.25-15.75,

    =57.5-(4.25+15.75),

    =57.5-20,

    =37.5;

    (2)125×32,

    =125×(8×4),

    =125×8×4,

    =1000×4,

    =4000;

    (3)[5/7]×16.31-[5/7]×2.31,

    =[5/7]×(16.31-2.31),

    =[5/7]×14,

    =10;

    (4)99×[7/98],

    =(98+1)×[7/98],

    =98×[7/98]+1×[7/98],

    =7+[7/98],

    =7[7/98];

    (5)0.76×0.25+[1/4]×0.24,

    =0.76×0.25+0.25×0.24,

    =0.25×(0.76+0.24),

    =0.25×1,

    =0.25;

    (6)[4/13]×0.8+[3/13]×80%+[4/5]×[6/13],

    =[4/13]×0.8+[3/13]×0.8+0.8×[6/13],

    =([4/13]+[3/13]+[6/13])×0.8,

    =1×0.8,

    =0.8.

    点评:

    本题考点: 小数的加法和减法;整数的乘法及应用;运算定律与简便运算;整数、分数、小数、百分数四则混合运算.

    考点点评: 根据题意,选择合适的运算定律进行简算即可.