计算下列各题.(能简算的要简算)

1个回答

  • 解题思路:(1)(4)先算乘法,再算加法;

    (2)先算乘法,再算减法;

    (3)根据减法的性质简算;

    (5)运用乘法分配律简算;

    (6)先把3.2分解成8×0.4,再运用乘法结合律简算.

    (1)19.4×6.1+2.3

    =118.34+2.3

    =120.64;

    (2)5.67×0.21-0.62

    =1.1907-0.62

    =0.5707;

    (3)10-0.72-0.28

    =10-(0.72+0.28)

    =10-1

    =9;

    (4)0.8×4.3+1.25

    =3.44+1.25

    =4.69;

    (5)63.8×1.57+1.57×36.2

    =(63.8+36.2)×1.57

    =100×1.57

    =157;

    (6)3.2×0.25

    =8×0.4×0.25

    =8×(0.4×0.25)

    =8×0.1

    =0.8.

    点评:

    本题考点: 小数四则混合运算.

    考点点评: 本题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进行简便计算.