Question

\(\dfrac{60}{7200}+\dfrac{60}{4200}\)=?     tính bằng cách quy đồng

 

Answer 1

\(=\dfrac{1}{120}+\dfrac{1}{70}=\dfrac{7+12}{840}=\dfrac{19}{840}\)

Answer 2

\(\dfrac{60}{7200}+\dfrac{60}{4200}=\dfrac{1}{120}+\dfrac{1}{70}\) (MSC: BCNN(120;70)=840)

\(=\dfrac{7}{840}+\dfrac{12}{840}=\dfrac{19}{840}\)

Answer 3

\(\dfrac{60}{7200} + \dfrac{60}{4200} = \dfrac{1}{120} + \dfrac{1}{70} = \) \(\dfrac{7}{84} + \dfrac{12}{84} = \dfrac{19}{84} \)