To find out how much weight the puppy gained, you can subtract the initial weight from the current weight:
Current weight: 12.25 pounds Initial weight: 4.5 pounds
Weight gained = Current weight - Initial weight Weight gained = 12.25 pounds - 4.5 pounds
To perform the subtraction:
12.25 - 4.5 = 12.25 - 4.50 = 7.75 pounds
The puppy gained 7.75 pounds.