To subtract fractions, all we need is a common denominator.
1×1=1 2×1=2 3×1=3
1×2=2 2×2=4 3×2=6
1×3=3 2×3=6
1×4=4
1×5=5
1×6=6
the least common denominator is 6
\(\frac{6}{6}\) = 1
\(\frac{3}{6} = \frac{1}{2}\)
\(\frac{2}{6} = \frac{1}{3}\)
\(\frac{6}{6} - \frac{3}{6} - \frac{2}{6}\)
=\(\frac{1}{6}\)
\(\frac{1}{6}\) of the tank is left