# Maths - How do I know that?

3rd February 2012 at 00:00

I was marking the other day and came across "x x x" in a rather disorganised script by a pupil called Jack. I stopped, puzzled. Had Jack needed a diversion midway through his trigonometry and turned to draft a love letter? But then I worked out what was happening, writes Jonny Griffiths.

Jack was writing the letter "x" and the times "x" in the same way. I dimly recalled when I had done the same, maybe 40 years ago. Who was it who had passed on the wisdom that the letter x was better written as two semicircles? (as in the picture above).

And what else was comparable in my mathematical make-up? I thought of the numeral 7 - I always put a line through it to differentiate it from the digit 1, and likewise with my letter z, to distinguish it from 2.

It made me wonder what other symbols I use without stopping to bring everyone on board. My pupils were keen to help, and it transpired that I abbreviate "positive" to "+ve" and "negative" to "-ve". For the majority, my shorthand was crystal clear, but those who skipped it, thinking Mr Griffiths would explain it in a minute, would have been disappointed.

What else?

For a colourful and fun way to introduce maths concepts, try languageisheartosay's collection.

Get pupils used to letters in maths with davecavell's "What's in my bag?" quiz.

If letters have a clear meaning, can algebra be easier? Beachman0274's starter task suggests it can.

Make algebra a game with kez84's top trumps animal cards.

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