A good reason to learn complex analysis: to prove that -10 = -10

Learned a lot from this tweet today:

So much, actually, that we had to go through it when my son came home from school . . .

First we talked about what multiplying by i does – you might even argue this is more important than knowing that -10 = -10. Who can really say, though?


Having learned a bit about what multiplying by i does geometrically, it was time for the big news of the day:


Ha ha – pretty much the perfect little math project for the end of the week 🙂

Paula Beardell Krieg’s Puff Boxes

Saw this super cool tweet from Paula Beardell Kreig today:

My son was home sick from school (for the 3rd day in a row 😦 ), but this looked like a fun and not too taxing project for him. He loved it:

I wasn’t home when he was working on the project, so I was excited to hear his thoughts when I got home. Unluckily (for me) he’d already given away the puff box as a thank you present by the time I got back. So, we started from the beginning:


It probably took him about 5 minutes to cut out the shape. When he finished he showed how to fold the shape to create the puff box. Fun little project!