Maths- Negative numbers
Published: November 6th, 2018
The other day I was working with negative numbers; something children are introduced to from about Year 6/7 in England. I’ve started to realise just how difficult it is for some young people to apply common sense and logic to this rather obscure concept. Working with positive (plus) and negative (minus) numbers appears to be a challenge for many children. It is easy to see why. Faced with problems such as: 7 – – 10, or -25 – 36, we can easily appreciate why some children struggle. Negative numbers can be difficult to get our heads around.
Although children start by looking at a number line, giving the line a context, such as money in and out of the bank, or temperatures moving up and down, helps children to apply the necessary logic. Consider banking. An account has £10 in, then we spend £12 (-£2) then put £20 into the account (£18), then take out £24 (-£6) and so on. Writing their own sum: 10 -12 + 20 – 24 enables learners to apply a practical context to the abstract method given by the school, aiding understanding as well as strengthening the memory.
Now consider temperature. It’s cold, just below freezing at -2, gets 2 degrees colder, then warms up by 5 degrees, warms up a further 3 degrees and so on, written as: -2 -2 +5 +3. Moving up and down the temperature scale makes it visual.
Particularly challenging are the ‘negative negatives’, and understanding that: – 8 – – 6 means that we are taking away -6 and therefore making the negatives fewer, thus moving up the number line, getting warmer, ending up at -2. Opposite to this is the idea that -8 -6 means adding both negatives together to get -14. No wonder children get confused.
In my view, what does not help is giving children a method to learn, without helping them to see why that method is as it is. Placing understanding before method is what I have stressed over the years, to many parents trying to help their children with maths.
PS. Have almost published ‘Support for children with Special Educational Needs and Disabilities: A parent’s guide’ the printed version of the ebook – part of my series : Parents: Help your child succeed.’ So watch out for it.
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