[3/18]+[2/18] 1-[4/12] [10/15]+[6/15]+[11/15] 2200-200÷25×4

1个回答

  • 解题思路:(1)(3)同分母分数相加,只把分子相加,分母不变;

    (2)把1写成[12/12],按同分母分数相加减的方法计算;

    (4)先算除法和乘法,再算减法;

    (5)把24看作6×4,运用乘法结合律简算;

    (6)把32看作4×8,运用乘法交换律与结合律简算;

    (7)(8)运用乘法分配律简算;

    (9)把98看作100-2,运用乘法分配律简算;

    (10)先算小括号内的,再算中括号内的,最后算括号外的;

    (11)先算括号内的,再算括号外的除法,最后算减法.

    (1)[3/18]+[2/18]=[5/18],

    (2)1-[4/12]=[2/3],

    (3)[10/15]+[6/15]+[11/15]=[9/5],

    (4)2200-200÷25×4,

    =2200-8×4,

    =2200-32,

    =2168;

    (5)24×25,

    =6×4×25,

    =6×(4×25),

    =6×100,

    =600;

    (6)125×25×32,

    =125×25×4×8,

    =(125×8)×(25×4),

    =1000×100,

    =100000;

    (7)165×65-65×65,

    =(165-65)×65,

    =100×65,

    =6500;

    (8)(90+125)×8,

    =90×8+125×8,

    =720+1000,

    =1720;

    (9)103×98,

    =103×(100-2),

    =103×100-103×2,

    =10300-206,

    =10094;

    (10)500-(521+504)÷25,

    =500-1025÷25,

    =500-41,

    =459;

    (11)24×[(7480-6480)÷100],

    =24×[1000÷100],

    =24×10,

    =240.

    点评:

    本题考点: 分数的加法和减法;整数的乘法及应用;整数四则混合运算.

    考点点评: 此题考查了整数、分数的四则混合运算,注意运算顺序和运算法则,灵活运用运算定律或运算技巧进行简算.