Question

Kathy is baking cakes. If each cake requires `1/12` of a teaspoon of vanilla, and she has `9/12` of a teaspoon, how many cakes can she bake?

Answer 1

She can bake `9` cakes.

Explanation:

Assuming she has enough of the other ingredients, the amount of vanilla is the limiting factor.

She can use it up `1/12` of a teaspoon at a time..

How many portions of `1/12` are there in `9/12`?

By observation and reasoning we can see it is `9`.

However, other questions might not be as obvious, so let's look at the math as well. We need to do a division operation...

`9/12 div 1/12" "larr` multiply by the reciprocal of `1/12`

`9/12 xx12/1 = 9` cakes

[note that in this case you can also just divide straight across because you get an exact answer for both]

`9/12 div 1/12 = (9div1)/(1div12) = 9/1 = 9` cakes