If the puppy weighs 8 1/8 pounds, you need to convert the entire number so that it has a denominator (bottom part of fraction) of 8, just like the 1/8 has.
Another way to say 1, with a denominator of 8, is 8/8, because 8 divided by 8 = 1.
So, if 1 = 8/8, then 2 is double the numerator (top part), but leave the bottom part the same: 16/8. This equals 2 because 16 divided by 8 equals 2. Keep going, and you find that 8 = 64/8. This is because 64 divided by 8 equals 8.
8 and 1/8 pounds really means 8 + 1/8 pounds. If 8 = 64/8, we can substitute this in for 8: 64/8 + 1/8. Since they have the same denominator (bottom part), we can add the numerators (top parts) together: (64+1)/8. 64+1=65, so the answer is D: 65/8.
Answer: D