We are told that a receipt requires 1/2 cup of flour for every 8 teaspoons of milk. To determine the amount of flour for 4 teaspoons of milk we can use the following method:
we divide the number of cups of flour over the number of teaspoons of milk, like this:
Solving we get:
Now we multiply by the number of teaspoons we require:
Solving we get:
This means that 4 teaspoons require 1/4 cup of flour. Another way to see it is that 4 teaspoons are half of 8 teaspoons, therefore they will require half the cups of flour, and half of 1/2 cup of flour are 1/4 cup of flour.