The Deadly Sins Of Maths

A Twitter conversation amongst Ben Ward got me thinking well-nigh a display idea...

There are about misconceptions in addition to mistakes that come upward up fourth dimension in addition to fourth dimension again. Last calendar week I gear upward a lovely Don Steward quadratics homework for my Year 11s in addition to was dismayed to run into a pose out of them utilization this:

(x + 2)² =  x² + 4

When I returned the homeworks I talked to the whole course of report well-nigh this mutual mistake. I told them that it makes me shout out every fourth dimension I run into it in addition to thus they must never ever utilization it again! When I asked them why it was wrong, they were able to explicate what had happened in addition to say me the right means to utilization it (phew!).

When I side past times side topographic point mutual misconceptions inward my students' work, I'm going to say the perpetrators that they've committed 1 of the deadly sins of maths, in addition to indicate them inward the direction of a classroom display. Making a large bargain well-nigh these mistakes (in a half-jokey means that volition stick inward their heads) is a skillful means to lower the direct chances of students repeating the same error inward an exam!

You tin download my posters here (there are twenty posters to pick from - y'all may non handgrip amongst all my choices). I've likewise made a US-friendly version (using the give-and-take math instead of maths) which y'all tin download here.

Some of these posters volition brand students halt in addition to mean value - it mightiness non live on obvious to them what the error is.

In our instruction nosotros should seek to preempt mutual misconceptions - this is where clever questioning in addition to well-written resources come upward into play. But sometimes nosotros can't run into mistakes coming - this is why effective marker in addition to feedback are essential.

These days marker doesn't get got to live on handwritten - websites similar Hegarty Maths can utilization it for you.

If you're looking for resources for highlighting in addition to tackling mutual misconceptions, hither are a few starting points:

• Classic Mistake Posters
• Sarah Carter's 'Killing Cats' poster 
• Curmudgeon's 'Do this in addition to the bunny dies'
• For H5N1 degree students, the constant character
• Mathsbox Big Mistake activity (I e'er piece of job this inward a GCSE revision lesson).
• here that links to diverse websites in addition to resources relating to mutual misconceptions.
  
  If y'all piece of job the 'deadly sins' idea, I'd dearest to listen how it goes!
  
  
  
  

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  Addendum:
  Two days subsequently creating this display, it was upward on @jase_jwanner's classroom wall.  He has likewise suggested creating a students' display called 'Maths Heaven', where they write downwards the right versions eg (-5)²=25.