Question

Tính nhanh:

7/10+3:10+2/5+1:10

Answer 1

\(\dfrac{7}{10}+3:10+\dfrac{2}{5}+1:10\\ =\left(\dfrac{7}{10}+\dfrac{2}{5}\right)+\left(3:10+1:10\right)\\ =\dfrac{11}{10}+\left(3+1\right)\times\dfrac{1}{10}\\ =\dfrac{11}{10}+4\times\dfrac{1}{10}\\ =\dfrac{11}{10}+\dfrac{2}{5}\\ =\dfrac{3}{2}\)

Answer 2

\(\dfrac{7}{10}+3:10+\dfrac{2}{5}+1:10\\ =\dfrac{7}{10}+\dfrac{3}{10}+\dfrac{2}{5}+\dfrac{1}{10}\\ =\left(\dfrac{7}{10}+\dfrac{3}{10}\right)+\left(\dfrac{2}{5}+\dfrac{1}{10}\right)\\ =\dfrac{10}{10}+\left(\dfrac{4}{10}+\dfrac{5}{10}\right)=\dfrac{10}{10}+\dfrac{5}{10}=\dfrac{15}{10}=\dfrac{3}{2}\)

Answer 3

= \(\dfrac{3}{2}\)