Question

[Edogawa Conan]

1) Tìm x

a) (1/4 x X - 1/8) x 3/4 = 1/4

b) 12/5 : X = 14/3 x 4/7

c) x + 2/3 = 8 : 4 - 1

2) Thực hiện phép tính:

a) (1/5 + 3/4) x 1/2

b) 13/20 - (1/4 - 5/20)

c) 1/10 + 4/20 + 9/30 + 25/50 + 36/60 + 49/70 + 64/80 + 81/90

d) 2/3.5 + 2/5.7 + 2/7.9 + ... + 2/41.43