The Problem with Chickens and Pigs

This is a question from our recent worksheet for 2nd grade. Can you solve it without equations and variables?

There are 13 chickens and pigs in a farm. The chickens and pigs have 40 legs altogether. How many chickens and pigs are there at the farm?

Yes, 2nd graders can solve this, using pictures and logic reasoning. Here is one way of solving:

Step 1: There are 13 animals.

Step 2: All animals have at least 2 legs. Add 2×13 = 26 legs.

Step 3: Add the rest of 40-26 = 14 legs, two each.

Answer: 7 pigs and 6 chickens.

And there you go, another step towards algebraic thinking, at 2nd grade.