Subtraction - how do you do it?



As our daughters move through school - we as parents are re-learning things with them that we studied ourselves in primary school.



One of the really basic things we are 'learning' is subtraction - in particular taking larger numbers away from smaller numbers. Euan and I both learned different methods of subtraction - and the method I learned is different to that being taught to our daughters, so I am having to re-learn how to subtract!



Take the above problem for example.  You would start on the right, with 2-7, which doesn't work, so what do you do..??







The method I learned - The Austrian 
Method!




So first I start with 2-7    .


This can't be done, so I add ten to the top and ten to the bottom.

In the top row, I add the 10 in the 'ones' , and in the bottom I add the 10 in the tens column, like this:


So now I have 12 - 7 = 5
and then            5 - 2  = 3



The problem works as you add an extra ten on both sides of the subtraction.  So long as you remember to mark the extra ten on both the top and the bottom!






The other method - what our daughters are learning!


This method only alters the numbers on the top row and involves crossing numbers out.  So here instead of adding numbers, you borrow from another column!  You borrow ten from the tens column and put that ten in the ones column, so:







So your problem now looks like this:

And then you have:


                       12 - 7 = 5
and then            4 - 1  = 3





Two different methods to produce the same result.

Now for me - of course the first method is easier - as that is what I was taught as a child.

But although I may be biased, I still think this method is easier and also neater than borrowing and crossing out, particularly when you have larger sums and you have to borrow from the hundreds or even the thousands column!  See the two different methods on this problem:



Of course it doesn't matter which method you use, or which your children learn.  It's probably best not to confuse them with both methods though!  And since our girls school is teaching the method of borrowing and crossing out, then when I help them with their homework, I need to help them using this method too!

What method do you use? and are your kids learning the same method? 







First Aid in English



I had the original version of this book when I was a kid.  I remember using it often, and enjoying reading the various lists found in the book - like sounds made by objects.
" the tick of a clock"
"the skirl of the bagpipes"

Or similes like.

"as tall as a giant'
"as purple as the heather"

Or group terms ..

"a pride of lions"
"a smuck of jellyfish" !!

There was always something interesting to find.

I'd quite forgotten about this book until our eldest daughter started studying things in English at school that reminded me of it.  So I ordered a copy from The Book Depository, which delivers free worldwide and has great prices.


Once the book arrived I was so happy to find that our daughters were interested in it too - and have been flicking through it and reading some of the more interesting parts!



It is a fabulous reference book for any student of English, and I used mine for many years!




Grammar points and useful vocabulary terms and phrases are introduced clearly, and then followed by some short exercises to practise them. There are also general tests, comprehension tests and spelling lists at the back of the book, that I'm sure we'll get lots of use out for some extra English practice here and there!


f you'd like to see more about this book or get your own copy of


Are there any great reference or educational books for kids that you can recommend?




(please note I have not been paid or given anything to endorse this book it is just my genuine opinion! - although the link will take you to the Book Depository site where I have an affiliate membership and do receive a commission for any sales from this website)