# Brennan has two pieces of wire, one 20 ft long and the other 12 ft long. If he wants to cut them up to produce many pieces of wire that are all of the same length, with no wire left over, what is the greatest length, in feet, that he can make them?

Both numbers, $20$ and $12$ are divisible by $2$ and $4$, but nothing else, so the longest length in feet with no wire left over (even lengths) is $8$ pieces of $4$ feet each.
$20$ can be evenly divided by $2$. $4$, $5$ and $10$.
$12$ can be evenly divided by $2$, $4$ and $6$.
The longest length (highest value) each can be divided into is $4$.