Students will learn how to solve proportions using inverse operations. They'll solve both word problems and mathematical ones. Then students will learn how to solve proportions by cross multiplying, and why it works. Again, they'll solve both word problems and mathematical ones. Here's an excellent video on why cross multiplying works.

Next, give your students these challenges:

- Tetrahedron Faces by NRICH

Mentally determine the area of the pinwheel:

Here's the solution.

Conclude by leading this investigation:

Lazy Toad Puzzles (counting, symmetry)

by MathPickle