Ta có:
(7/9 - 1/2) - (1/2 - 2/9)
= (14/18 - 9/18) - (9/18 - 4/18)
= 5/18 - 5/18
= 0/0
= 0.
\(\left(\frac{7}{9}-\frac{1}{2}\right)-\left(\frac{1}{2}-\frac{2}{9}\right)=\frac{7}{9}-\frac{1}{2}-\frac{1}{2}+\frac{2}{9}=\left(\frac{7}{9}+\frac{2}{9}\right)-\left(\frac{1}{2}+\frac{1}{2}\right)=1-1=0\)
= \(\left(\frac{14}{18}-\frac{9}{18}\right)-\left(\frac{9}{18}-\frac{4}{18}\right)\)
= \(\frac{5}{18}-\frac{5}{18}\)
= \(1\)
kick nha
0/0 nha bn