Question

1,tính:

a,1/2x2/3x3/4=                      b,7/8x8/9x9/10=

c,5/14x7/15x28/7=                d,2x1/2x3x1/3x4x1/4x5x1/5=

2,tính:

a,7/20-(5/8-3/5)=                   b,5/6+(5/9-1/4)=                    

c,9/10-(2/5+3/10)+7/20=

3,tìm x:

a,1/2+x=5/6              b,5/6-x=1/3         c,x-1/=3/10         d,1/3x x=1/6

Answer 1

Bài 1: Tính
a, 1/2 x 2/3 x 3/4 = 1/4
b, 7/8 x 8/9 x 9/10 = 7/10
c, 5/14 x 7/15 x 28/7 = 2/3
d, 2 x 1/2 x 3 x 1/3 x 4 x 1/4 x 5 x 1/5 = 1
Bài 2: Tính
a, 7/20 - ( 5/8 - 3/5 ) = 7/20 - 1/40 = 14/40 - 1/40 = 13/40
b, 5/6 + ( 5/9 - 1/4 ) = 5/6 + 11/36 = 30/36 + 11/36 = 41/36
c, 9/10 - ( 2/5 + 3/10 ) + 7/20 = 9/10 - 7/10 + 7/20 = 2/10 + 7/20 = 4/20 + 7/20 = 11/20.
Bài 3: Tìm x:
a, 1/2 + x = 5/6
x = 5/6 - 1/2
x = 1/3
b, 5/6 - x = 1/3
x = 5/6 - 1/3
x = 1/2
c, x - 1/mấy vậy bạn
d, 1/3 x x = 1/6
x = 1/6 : 1/3
x = 1/2