Respuesta :

3 litters, 7 puppies in each litter, 3 x 7= 21 puppies last year
in this situation, you are finding how many puppies per litter. you know that there are 3 litters, and that there are 7 puppies per litter, so if you add 7 three times, you get 21. another way you can find it is that you multiply 7*3=21