Answer: Eva's dog actually gained 3/8 pounds ( 0.375pounds)
Explanation:
Step 1
Given that
old weight = 1 7/8 pounds
New weight = 2 1/4 pounds
weight gained = New weight - Old weight
Step 2
weight gained = New weight - Old weight
2 1/4 pounds - 1 7/8 pounds
2.25 pounds - 1.875 pounds
0.375pounds = 3/8 pounds