How can you use a rate to compare the costs of two boxes of cereal that are different sizes?

Price of box of cereal #1
= $ per ounce(or other unit)
Size of box #1 (in ounces,
or some other unit)

Price of box of cereal #2
= $ per ounce(or other unit)
Size of box #2 (in ounces,
or some other unit)

Whichever has the smaller answer (the cost is the least per ounce) is the best deal.

Oh yeah yeah the answer is oh yeah yeah