Question

A jar contains 8 4/9 pounds of jam. If Sam eats 3 2/5 pounds of the jam, how many pounds of jam remains in the jar?

Answer 1

$\bf 8\frac{4}{9}\implies \cfrac{8\cdot 9+4}{9}\implies \cfrac{76}{9} \\\\\\ 3\frac{2}{5}\implies \cfrac{3\cdot 5+2}{5}\implies \cfrac{17}{5}\\\\ -------------------------------\\\\ \cfrac{76}{9}-\cfrac{17}{5}\impliedby \textit{let's use an LCD of 45}\implies \cfrac{5\cdot 76-9\cdot 17}{45} \\\\\\ \cfrac{380-153}{45}\implies \cfrac{227}{45}\implies \boxed{5\frac{2}{45}} \\\\\\ 5\frac{2}{45}\implies \cfrac{5\cdot 45+2}{45}\implies \cfrac{227}{45}$