Exemple !

Grandma has 10 ducks, 7 chickens and 2 cats in the yard. How many feet do the animals have in total?

We know that ducks and chickens have 2 legs and cats have 4 feet.

We multiply the number of animals by the number of feet.

10 × 2 + 7 × 2 + 2 × 4 =

20 + 14 + 8 = 42