Question 1039583
This recipe is for 16 Brownies, but I only need 12. Can you help me with this equation?

1/2 cup Butter
2 1/2 ounce unsweetened chocolate
1/2 cup sugar
1/2 teaspoon vanilla
2 Eggs
3/4 cup flour 
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If this is a math problem:
12/16 = 3/4
Multiply all the number by 3/4.
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If you're actually making brownies, make 16.  What difference does 4 more make?