Divide & Conquer

by Dave Godfrey

The other day I was working with sets of teachers from different phases in a Rochdale school. A session with with Upper Key Stage 2 staff was preceded by a session with KS1 staff. The KS1 session concluded with a plea for a powerful image for division by grouping. As I often do, I turned to an image created using the Numicon shapes. I used the accompanying PowerPoint slide before exploring it’s power practically with the teachers. Each set of the Numicon shapes that you can see on the slide are sitting on top of two blue 10 pieces, therefore representing 20. The other shapes are placed on top. I would recommend the verbal phase: “20 divided by 3, means how many 3s can I fit into 20.” By fitting 3 pieces on top of the two 10 pieces, it soon becomes very obvious that you can fit 6, 3 pieces in 20 with a remainder of 2 (identified by a two piece). This very simple image is incredibly powerful and provides children (and teachers!) with a turn to image that reveals the conceptual understanding behind of division by grouping.

The KS1 staff went away equipped for division! The Upper Key Stage 2 staff kicked off their session requesting an image for finding the nth term in a linear sequence … again the Numicon shapes came to the rescue!

You can check out a host of great ideas on 22nd January at the Village Hotel in Dudley! See you there!

Division by Grouping Slide.145

About the author:
Dave is a member of the ‘Sense of Number’ Maths Consultancy Team, a Numicon Affiliate Trainer and an Accredited PD Leader with NCETM.
www.senseofnumber.co.uk
Dave’s work includes Maths training for Primary staff, Number Fun Activity Days in schools and the creation of resources for Primary mathematics.
After spending four terms teaching in a York Primary school during 2011 and 2012, Dave’s Mathematics training courses come packed with engaging ideas, relevant theory and recent classroom experience.
Dave is a Numicon Affiliate Trainer and an accredited PD Leader for the new National Curriculum with the National Centre for Excellence in the Teaching of Mathematics.
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