Answer:
1/2 teaspoons of vanilla would be too much, the correct amount to use would be 0.125 teaspoons.
Step-by-step explanation:
Since 1 stick butter, 1/2 cup sugar, 1/2 teaspoon vanilla, 3 tablespoons milk, 1 1/2 cup flour, 2 teaspoon baking powder, 1/4 teaspoon salt is the regular recipe for 20 cookies, we would first have to divide 20 by 5 which would equal 4. And just like we had to divide the number of cookies down we have to divide the amount of vanilla down. So now we could turn 1/2 into a decimal which is 0.5. And 0.5 divided by 4 is 0.125.
So Edwin would need 0.125 teaspoons of vanilla so 0.5 ( 1/2 ) teaspoons of vanilla would be too much.