Question

Tính rồi viết kết quả dưới dạng số thập phân:

a) 1/2+1/4-1/5                                             b) 1/2x2/5: 1/4

 

Answer 1

 

 4.
a. 1/2 + 1/4 + 1/5
= 1*10/20 + 1*5/20 + 1*4/20
= (10 + 5 + 4)/20
= 19/20
= 0,95
b.1/2 * 4/5 : 1/4
= (1*4/2*5) : 1/4
= 4/10 : 1/4
= 2/5 * 4
= 8/5
= 1,6

Answer 2

`a) 1/2 + 1/4 + 1/5`
`=10/20 + 5/20 + 4/20`
`= 19/20`

`b)1/2xx 4/5 : 1/4`
`= 4/10 : 1/4`
`= 8/5`

Answer 3

\(a\)/ \(\dfrac{1}{2}+\dfrac{1}{4}-\dfrac{1}{5}=\dfrac{11}{20}\)

\(b\)/ \(\dfrac{1}{2}.\dfrac{4}{5}:\dfrac{1}{4}=\dfrac{8}{5}\)

Answer 4

a) 1/2 + 1/4 - 1/5= 10/20 + 5/20 - 4/20 = 15/20 - 4/20 = 11/20 
b) 1/2 x 2/5 : 1/4 = 10/20 + 8/20 : 5/20 = 18/20 : 5/20 = 8/5