To find out how many ounces less the caterpillar weighs than the dog, you have to convert to dog's weight in pounds to his weight in ounces.
Pounds and ounces are two completely different units of weight, and since they are different, they cannot be added or subtracted normally.
To convert the dogs weight to ounces, you need to know how many ounces are in a pound. 16 ounces are on a pound. Since the dog is 10 pounds, it has a total weight of 160 ounces.
Subtract the caterpillar's weight from the dog's weight to find your answer