脱式计算(能简算的要简算)(1)4.65-1.55-1.45 (2)58.1-29.7÷3 (3)201×3.5-3.5

1个回答

  • 解题思路:(1)运用减法的性质简算;

    (2)先算出发,再算剑法;

    (3)(4)运用乘法分配律简算.

    (1)4.65-1.55-1.45,

    =4.65-(1.55+1.45),

    =4.65-3,

    =1.65;

    (2)58.1-29.7÷3,

    =58.1-9.9,

    =58.1-(10-0.1),

    =58.1-10+0.1,

    =48.2;

    (3)201×3.5-3.5,

    =(201-1)×3.5,

    =200×3.5,

    =700;

    (4)2.2×0.25+0.25×1.8,

    =(2.2+1.8)×0.25,

    =4×0.25,

    =1.

    点评:

    本题考点: 整数、分数、小数、百分数四则混合运算;运算定律与简便运算.

    考点点评: 考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律简算.