Question

[Mạc Nhược Khánh Nghi]

Tính bằng cách thuận tiện nhất :

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

b) (1 - 1/2) x (1 - 1/3) x ( 1 - 1/4)

Answer 1

[Nguyễn Tiến Dũng]

a)\(\left(1+\frac{1}{2}\right)\left(1+\frac{1}{3}\right)\left(1+\frac{1}{4}\right)=\frac{3}{2}\cdot\frac{4}{3}\cdot\frac{5}{4}=\frac{3.4.5}{2.3.4}=\frac{5}{2}\)

b)\(\left(1-\frac{1}{2}\right)\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right)=\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{3}{4}=\frac{1.2.3}{2.3.4}=\frac{1}{4}\)