Category Archives: Diagrams and decorations

Number and numeration gone wrong

This came from a workbook bought by the kids’ grandparents.

Can someone please explain the purpose of the jars of bugs here?



Diagrams, week 10 (bonus)


A former calculus student who is tutoring in a local elementary school stopped by to ask about how and why decimal points work in the lattice algorithm for multi digit multiplication. Here’s the residue of our conversation.

Diagrams, week 10


A student submission in response to the question, “Can a hexagon be equiangular, yet have no two sides congruent?” This is presently an A Assignment in my math for elementary teachers course, and is still open (although this diagram purports to resolve it with a counter example).

Diagrams, week 9


Griffin’s scratch paper. He needed to find 29 divided by 2 on his third grade homework.

Diagrams, week 8 (late)


A College Algebra student wondered whether there could be a function such that its inverse is the same as its opposite. That is, can there be an f such that f^{-1}(x)=-f(x)?

I had to work graphically to think this through, which you see above.

That task is now an A Assignment.