简算2.5×8×0.4×0.125 0.65×201 6.81+6.81×99 (1×2×3…10×11)÷(27×25

2个回答

  • 解题思路:(1)2.5×8×0.4×0.125,运用乘法的交换律和结合律进行简算;

    (2)0.65×201,运用乘法分配律进行简算;

    (3)6.81+6.81×99,运用乘法分配律进行简算;

    (4)(1×2×3…10×11)÷(27×25×24×22),将除数转化为:(11×2×6×4×5×5×3×9),再根据除法与分数的联系写成分数的形式,然后进行约分即可;

    (1)2.5×8×0.4×0.125,

    =(2.5×0.4)×(8×0.125),

    =1×1,

    =1;

    (2)0.65×201,

    =0.65×200+0.65×1,

    =130+0.65,

    =130.65;

    (3)6.81+6.81×99,

    =6.81×(1+99),

    =6.81×100,

    =681;

    (4)(1×2×3…10×11)÷(27×25×24×22),

    =(1×2×3…10×11)÷(11×2×6×4×5×5×3×9),

    =[1×2×3…×10×11/11×2×6×4×5×5×3×9],

    =7×8×2,

    =112;

    点评:

    本题考点: 运算定律与简便运算.

    考点点评: 解决简算的题目,一定要仔细审题,运用运算技巧或运算定律,灵活简算.