Question

简单几道算术题。(六年级)

能简便尽量简便。 1/5÷18/25-(减)5/24÷5/6 (60%+4/9×50%)÷37/60-(减)5/6 (40%+1/3)÷2/3×(1-(减)75%) 列式计算。 一个数是600，比另一个数多20%。求另一个数。(列方程)

Answer 1

1.
1/5÷18/25-(减)5/24÷5/6
=1/5×25/18-5/24×6/5
=5/18-1/4
=10/36-9/36
=1/36
2.(60%+4/9×50%)÷37/60-(减)5/6
=(6/10+4/9×1/2)×60/37-5/6
=(54/90+20/90)×60/37-5/6
=74/90×60/37-5/6
=4/3-5/6
=8/6-5/6
=1/2
3.(40%+1/3)÷2/3×(1-(减)75%)
=(4/10+1/3)×3/2×25%
=(4/10
×3/2
+1/3
×3/2)×1/4
=(6/10+1/2)×1/4
=(6/10+5/10)×1/4
=11/10×1/4
=11/40
4.一个数是600，比另一个数多20%。求另一个数。(列方程)
解:设另一个数为x。
x(1+20%)=600
x=600÷1.2
x=500