Question

Bài 1.  Thực hiện phép tính (tính hợp lý nếu có thể): a) 5/11 + 11/12  b) 1 /7 + 9/27 + - 4/7 + 10/7

 

Answer 1

  \(\dfrac{1}{7}+\dfrac{9}{27}+\dfrac{-4}{7}+\dfrac{10}{7}\)

= \(\dfrac{1}{7}+\dfrac{1}{3}+\dfrac{-4}{7}+\dfrac{10}{7}\)
= \(\left(\dfrac{1}{7}+\dfrac{-4}{7}+\dfrac{10}{7}\right)+\dfrac{1}{3}\)
= \(\left(\dfrac{1+\left(-4\right)+10}{7}\right)+\dfrac{1}{3}\)
= \(\dfrac{7}{7}+\dfrac{1}{3}\)
= \(1+\dfrac{1}{3}\)
= \(\dfrac{3}{3}+\dfrac{1}{3}\)
= \(\dfrac{4}{3}\)

Answer 2

bn ơi ý a cậu có ghi sai ko ạ

 

Answer 3

a) \(\dfrac{-5}{12}+\dfrac{11}{12}\)
=  \(\dfrac{\left(-5\right)+11}{12}\)
= \(\dfrac{6}{12}\)
= \(\dfrac{1}{2}\)