Question

Tính: 2/5+7/12+4/15

Answer 1

\(\dfrac{2}{5}+\dfrac{7}{12}+\dfrac{4}{15}\\ =\dfrac{2.12}{5.12}+\dfrac{7.5}{12.5}+\dfrac{4.4}{15.4}\\ =\dfrac{24}{60}+\dfrac{35}{60}+\dfrac{16}{60}\\ =\dfrac{24+35+16}{60}\\ =\dfrac{75}{60}\\ =\dfrac{75:15}{60:15}\\ =\dfrac{5}{4}\)

Answer 2

\(\dfrac{2}{5}+\dfrac{7}{12}+\dfrac{4}{15}\)

\(=\left(\dfrac{6}{15}+\dfrac{4}{15}\right)+\dfrac{7}{12}\)

\(=\dfrac{10}{15}+\dfrac{7}{12}\)

\(=\dfrac{5}{4}\)