Respuesta :
					                   To solve, subtract Chrissy's age from the sum.
37 - 25 = 12
Chrissy's dog is 12 years old.
					                
					             37 - 25 = 12
Chrissy's dog is 12 years old.
					                   The answer is 37-25= 12
25 year Chrissy + 12 year old dog= the sum of their ages
					                
					             25 year Chrissy + 12 year old dog= the sum of their ages
