A ratio can be written in three different ways:
x to y
x:y
x/y
These all mean dividing.
For example, one package contains 20 cookies so the equation would be:
20/1 so to find how many cookies are in 2 packages you would multiply 20 by 2 which would equal 40 so the equation would equal 40/2 which means 40 cookies in 2 packages.