Question

tính nhanh 

2/5 + 7/12 + 13/12

Answer 1

2/ 5 + 7/ 12 + 13 /12 = 2/ 5 + 20/ 12 = 2/ 5 + 5/ 3 = 6/ 15 + 25/ 15 = 31/ 15

Answer 2

\(=\dfrac{2}{5}+\left(\dfrac{7}{12}+\dfrac{13}{12}\right)\)

\(=\dfrac{2}{5}+\dfrac{5}{3}\)

\(=....\)

Answer 3

2/5 + 7/12 + 13/12

= 2/5 + 20/12

= 2/5 + 5/3

= 6/15 + 25/15

= 31/15

Answer 4

\(\dfrac{2}{5}+\dfrac{7}{12}+\dfrac{13}{12}=\dfrac{2}{5}+\dfrac{5}{3}=\dfrac{31}{15}\)