脱式计算,能简算的要简算: 46.5×99+46.5 12.5÷2.5÷0.4  2

1个回答

  • 解题思路:(1)把46.5看作46.5×1,运用乘法分配律简算;

    (2)按除法的性质简算;

    (3)先算2.6÷2.6,再按计算顺序简算;

    (4)先算括号中的加法,再算括号外的除法;

    (5)先算小括号括号内的减法,再算中括号内的乘法,最后算括号外的除法.

    (6)先算括号内的除法,再算括号内的乘法,最后算括号外的乘法.

    (1)46.5×99+46.5

    =46.5×(99+1)

    =46.5×100

    =4650

    (2)12.5÷2.5÷0.4

    =12.5÷(2.5×0.4)

    =12.5÷1

    =12.5

    (3)2.6×1.9÷2.6×1.9

    =2.6÷2.6×1.9×1.9

    =1×1.9×1.9

    =3.61

    (4)(7.7+1.54)÷0.7

    =9.24÷0.7

    =13.2

    (5)10.8÷[(4.62-1.92)×4]

    =10.8÷[2.7×4]

    =10.8÷10.8

    =1

    (6)2.6×(2.139÷9.3×6.2)

    =2.6×(0.23×6.2)

    =2.6×1.426

    =3.7076

    点评:

    本题考点: 小数四则混合运算;运算定律与简便运算.

    考点点评: 此题考查了小数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.