Hi! This question is essentially asking for the highest common factor for 72 and 96! The question is asking for the longest pieces of equal sized bars that could be cut from both 72cm and 96cm! We can solve this by trial and error, where you plug in values to see if both bars could be cut into a complete number. Doing so will make you realise that 24cm pieces are the longest possible ones that can be cut :) feel free to clarify further if needed!