Monday 19 May 2014

Back to basics with addition and subtraction

I've taught my class to add and subtract using lots of different strategies throughout the year but still felt there were some children who didn't have one completely secure strategy for solving addition and subtraction problems.

I decided to go right back to basics and make sure that we could all add using the dienes equipment and that everyone felt really secure using this. I think I am guilty (having moved from teaching 10-11 year olds to 6-7 year olds) of assuming the children know how to use the maths equipment I give them and don't actually teach them how to use it sometimes!

I made some Tens and Units (or Tens and Ones) frames to use (see my freebies section) and off we went...




I started off by modelling how to play a simple 'build it' game using the visualiser. They rolled the dice to generate numbers to add and aimed for different totals depending on how confident they were. Some used 0-9 dice and just added ones each time and others used the place value dice to add bigger numbers. They loved making this a game by winning if they were the one to roll the number that hit (or took them over) their target number!


I kept stopping them to model again and pulled groups or pairs who were struggling to work with me using the magnetic dienes on my flipchart.



Once they were feeling more confident we moved on to recording addition problems (from addition and subtraction question cards). I had 4 different levels of addition cards hanging in colourful bags at the front of the class (they love choosing their own questions). I guided some to certain bags to challenge or support, but let other choose depending on how confident they felt.


 

I was really happy with how everyone finally got it and were talking about what they were doing when they rolled a number that meant they tipped into the next ten!

We then moved on to subtraction and started in the same way but playing the game 'demolish it' this time. They started with 30 and rolled the dice to see how many they had to take away. While they certainly enjoyed the game and keeping score of who was the winner (whoever rolled the number that meant they had 0 left), some definitely did not get it and seemed to alternate adding and subtracting! Lots more practice needed there...




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