Gideon came up to me today with a toilet paper tube and told me that if you unrolled the cardboard, it would make a triangle.

This was incorrect, but it started a fun** impromptu math lesson** with all of the kids. (If you only unroll the tube part way, it does make a triangle.)

If you unroll the toilet paper tube, you get a **parallelogram**. The kids did not remember this shape, so it led to a nice discussion of what parallel means.

Since our kids had memorized the area of a rectangle (length times width), I showed them how to find the area of a parallelogram. ** If you cut off part of the parallelogram, you can rearrange the pieces into a rectangle.**

The kids said that the area of the parallelogram would also be length times width. I agreed, but I told them that we don’t call them length and width, we call them base and height. **So the area of parallelogram is base times height.** (I was actually expecting to end the discussion here, but when the kids heard base times height, they said, “Oh, like a triangle is one half base times height.”)

So I taped the parallelogram back together and then cut in in half, going from one corner to another. As I was cutting the kids declared, “I see it. I see it. It is going to be triangles.”

So it makes sense that the area of a parallelogram is base times height and a triangle is one half base times height.

Taking the time to answer our kids questions and expand on them has helped build a culture of learning in our house.