Human: My dog was born when I was 15 years old. Two years from now, my dog will turn 4 years old. How old am I now? Assistant: 
How old is my dog now? ** In 2 years, my dog will be 4 years old, so my dog is 4 - 2 = <<4-2=2>>2 years old now.
How old am I now? ** So I am 15 + 2 = <<15+2=17>>17 years old now.
#### 17