In order to find the weight of Mitten last year, we just need to subtract its current weight and the amount it increased.
So we have that:
[tex]\begin{gathered} 7\frac{2}{7}-1\frac{4}{7}=7+\frac{2}{7}-(1+\frac{4}{7}) \\ =7+\frac{2}{7}-1-\frac{4}{7}=6-\frac{2}{7}=5+1-\frac{2}{7}=5+\frac{7}{7}-\frac{2}{7}=5+\frac{5}{7}=5\frac{5}{7} \end{gathered}[/tex]So Mitten's weight last year was 5 5/7 pounds.
