Lesson 6.4 of Exploding Dots

From a channel Lumen includes in full: James Tanton, a maths educator and former MAA mathematician-at-large, shows how to think through maths problems with visual approaches (exploding dots, arithmetic and algebra).

A 6-minute video from James Tanton's catalogue; the title names its topic.

Video by James Tanton, played through YouTube's embedded player.