2 :)

1

câu 40 dễ nhìn mà ?

c)
\(\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{6}=\dfrac{3}{6}+\dfrac{2}{6}+\dfrac{1}{6}=\dfrac{6}{6}=1\)
\(\dfrac{5}{12}+\dfrac{5}{6}-\dfrac{3}{4}=\dfrac{5}{12}+\dfrac{10}{12}-\dfrac{9}{12}=\dfrac{5}{12}+\dfrac{1}{12}=\dfrac{6}{12}=\dfrac{1}{2}\)
\(1-\left(\dfrac{1}{5}+\dfrac{1}{2}\right)=\dfrac{10}{10}-\left(\dfrac{2}{10}+\dfrac{5}{10}\right)=\dfrac{10}{10}-\dfrac{7}{10}=\dfrac{3}{10}\)

câu cuối "nên thôi không ghi nữa" :)

have not viết tách ra hoặc viết tắt là haven't

It's a month since they last ate out. (since)

- They..haven't eaten out since last month.