Partition a rectangle into rows and columns of same-size squares and count to find the total number of them.
Find the area of a rectangle by counting unit squares. This builds on the ability to skip-count. Next, give your students this challenge, in which areas can be determined by counting unit squares or by cutting up and rearranging triangles:
Problem: What are the areas of the squares you can make on a \(4 \times 4\) Geoboard? (source).
Solution: \(1, 2, 4, 5, 9\)
Lastly, give your students this challenge.
Note: Even though the last challenge has nothing to do with area, I have placed the challenge here because both the challenge and this lesson require graph paper. Might as well do the challenge while they have their graph paper out.