计算.[5/8+1112+38+112](13+14+16)×24[7/8×7+78](12+613)×131262.5

1个回答

  • 解题思路:(1)利用加法交换律与结合律简算;

    (2)(3)(4)(5)利用乘法分配律简算.

    (1)[5/8]+[11/12]+[3/8]+[1/12]

    =[5/8]+[3/8]+([1/12]+[11/12])

    =1+1

    =2;

    (2)([1/3]+[1/4]+[1/6])×24

    =[1/3]×24+[1/4]×24+[1/6]×24

    =8+6+4

    =18;

    (3)[7/8]×7+[7/8]

    =[7/8]×(7+1)

    =[7/8]×8

    =7;

    (4)(12+[6/13])×[13/12]

    =12×[13/12]+[6/13]×[13/12]

    =13+[1/2]

    =13[1/2];

    (5)62.5×[1/5]+[4/5]×62.5-62.5

    =62.5×([1/5]+[4/5]-1)

    =0.

    点评:

    本题考点: 分数的四则混合运算;运算定律与简便运算.

    考点点评: 此题考查分数的简便运算,根据数字与符号特点灵活选用运算定律简算.