subtraction
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I'm a fan of number lines too Guest55!
especially with children who have difficulty with maths. Rulers make really good impromptu number lines (metre rules too!)
The numeracy strategy used number lines a lot when it was introduced.
I had a washing line in my classroom and we pegged numbers on it..
I'm a believer in kinaesthetic stuff
especially with children who have difficulty with maths. Rulers make really good impromptu number lines (metre rules too!)
The numeracy strategy used number lines a lot when it was introduced.
I had a washing line in my classroom and we pegged numbers on it..
I'm a believer in kinaesthetic stuff
Hi WP
21003 - 14638
in columns
2 1 0 0 3
1 4 6 3 8
There are two ways of verbalising the question
1. Is to say three take away eight, can't do
or
2. Eight from three, can´t do.
I prefer the first, because it is worded in the correct order of the question.
You need to make 3 bigger than 8, by converting numbers into their next lowest value.
i.e. A ten becomes ten units, one hundred becomes ten tens, one thousand becomes 10 hundreds.
So, the 1 in the thousand column becomes 0, making the 0 in the hundreds column 10.
The 10 in the hundreds column becomes 9, making the 0 in the tens column 10.
The 10 in the tens column becomes 9 and the 3 in the units column becomes 9.
Giving the following
2 0 9 9 13
1 4 6 3 8
You cab now work out, from right to left, the first part of the sum
13 - 8 = 5
9 - 3 = 6
9 - 6 = 3
Next, the 2 in the 10,000 column becomes 1 and the 0 in the thousand column becomes 10, giving the next part of the sum
10 - 4 = 6
and
1 - 1 = 0
Giving the answer 6365
Regards
Mike
21003 - 14638
in columns
2 1 0 0 3
1 4 6 3 8
There are two ways of verbalising the question
1. Is to say three take away eight, can't do
or
2. Eight from three, can´t do.
I prefer the first, because it is worded in the correct order of the question.
You need to make 3 bigger than 8, by converting numbers into their next lowest value.
i.e. A ten becomes ten units, one hundred becomes ten tens, one thousand becomes 10 hundreds.
So, the 1 in the thousand column becomes 0, making the 0 in the hundreds column 10.
The 10 in the hundreds column becomes 9, making the 0 in the tens column 10.
The 10 in the tens column becomes 9 and the 3 in the units column becomes 9.
Giving the following
2 0 9 9 13
1 4 6 3 8
You cab now work out, from right to left, the first part of the sum
13 - 8 = 5
9 - 3 = 6
9 - 6 = 3
Next, the 2 in the 10,000 column becomes 1 and the 0 in the thousand column becomes 10, giving the next part of the sum
10 - 4 = 6
and
1 - 1 = 0
Giving the answer 6365
Regards
Mike
Mike Edwards is a co-author of The Tutors product range.
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- Posts: 888
- Joined: Wed Aug 01, 2007 12:19 pm
Lol, me too then!
Not everything's about school and tests, is it? Or are we supposed to spend the rest of our lives with a calculator in our pockets, ready to use it in appropriate situations? I'd like my children to know how to do sums like that in their heads and on paper, and so far 3/4 of them do. (Just the 5 year old to go!)
Not everything's about school and tests, is it? Or are we supposed to spend the rest of our lives with a calculator in our pockets, ready to use it in appropriate situations? I'd like my children to know how to do sums like that in their heads and on paper, and so far 3/4 of them do. (Just the 5 year old to go!)
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- Posts: 888
- Joined: Wed Aug 01, 2007 12:19 pm
Doing £210.03 - £146.38 for some reason? I've certainly done similar calculations to that recently - transferring money to and from bank accounts, for example - I can see a couple on my desk in front of me, lol.
Or reading your electricity meter, and wanting to work out how many units you've used.
Or keeping track of the mileage on your car so you know how far you've gone on a tank of petrol.
Etc.
Or reading your electricity meter, and wanting to work out how many units you've used.
Or keeping track of the mileage on your car so you know how far you've gone on a tank of petrol.
Etc.