Why do we use x in algebra as the unknown? I got asked this question today by some of my top set year 10, and I could see from their faces that they felt they had got me.
“Sir, why do we use x as the unknown in algebra”, now they thought they had caught me out when I said get on with your work and went to my machine. Little did they know that I was lining up a response to the question with this video. The TED video below is very short but makes a great plenary or starter to a lesson on Algebra. It would be useful to have a discussion after the video to assess whether learners understood what the video was illustrating. Enjoy.