0.2(63=0.2+0.0(63)=0.2+\(\frac{63}{10.99}\)
\(\frac{0,2\cdot990+63}{990}=\frac{2043}{990}\)tu kiem tra xem no toi gian chua
bao ban tu kiem tra toi gian chua ma:
\(\frac{2043}{990}=\frac{2043:9}{990:9}=\frac{227}{110}\)
\(k\ge1\Rightarrow lansau\le3phut\)
neu \(k=0\Rightarrow lansau=0\)