Answer:
You have 21 muffins left.
Step-by-step explanation:
Well since you have 28 muffins up you gave 1/4 to your friend...
Your first step is to multiply 28 by 1/4 to get how much you gave your friend.
28 * 1/4 = 7
Seven is how much you gave your friend. In Step 2, all you have to do is subtract how much you originally (28) had with how much you gave your friend (7).
28 - 7 = 21
You have 21 muffins left. Hope this helped!