counting up to subtract
Post on 23-Jun-2015
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Subtraction of Whole Numbers by Counting Up, Using A Column
Method(the 2nd step towards using a standard
written method for subtraction)
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To “Count Up” you need to add on from the smaller number to the larger number in stages. To record it using a column method you need to first be able to record it on a number line. For example 86 – 47 = 39:
+ 6 + 30
47 50 86
+ 3
56
To “Count Up” you need to add on from the smaller number to the larger number in stages. To record it using a column method you need to first be able to record it on a number line. For example 86 – 47 = 39:
This can thenbe developedinto a columnmethod:
+ 6 + 30
47 50 86
+ 3
56
8 6
- 4 7
To “Count Up” you need to add on from the smaller number to the larger number in stages. To record it using a column method you need to first be able to record it on a number line. For example 86 – 47 = 39:
This can thenbe developedinto a columnmethod:
+ 6 + 30
47 50 86
+ 3
56
8 6
3- 4 7
50
To “Count Up” you need to add on from the smaller number to the larger number in stages. To record it using a column method you need to first be able to record it on a number line. For example 86 – 47 = 39:
This can thenbe developedinto a columnmethod:
+ 6 + 30
47 50 86
+ 3
56
8 6
3- 4 7
50
6 56
To “Count Up” you need to add on from the smaller number to the larger number in stages. To record it using a column method you need to first be able to record it on a number line. For example 86 – 47 = 39:
This can thenbe developedinto a columnmethod:
+ 6 + 30
47 50 86
+ 3
56
8 6
3- 4 7
50
6 56
3 0 86
To “Count Up” you need to add on from the smaller number to the larger number in stages. To record it using a column method you need to first be able to record it on a number line. For example 86 – 47 = 39:
This can thenbe developedinto a columnmethod:
+ 6 + 30
47 50 86
+ 3
56
8 6
3- 4 7
50
6 56
3 0 86
3 9
As you becomemore confident,the number ofsteps can be reduced:
8 6
- 4 7
As you becomemore confident,the number ofsteps can be reduced:
8 6
9- 4 7
56
As you becomemore confident,the number ofsteps can be reduced:
8 6
9- 4 7
56
3 0 86
As you becomemore confident,the number ofsteps can be reduced:
8 6
9- 4 7
56
3 0 86
3 9
Counting up can also be used with 3 digit numbers, for example: 335 – 177 = 158. Firstly, using a number line:
+ 20 + 100
177 200 300
+ 3
180 335330
+ 5+ 30
330335
Counting up can also be used with 3 digit numbers, for example: 335 – 177 = 158. Firstly, using a number line:
Then usingthe columnmethod:
3 3 5
- 1 7 7
+ 20 + 100
177 200 300
+ 3
180 335330
+ 5+ 30
Counting up can also be used with 3 digit numbers, for example: 335 – 177 = 158. Firstly, using a number line:
Then usingthe columnmethod:
3 3 5
3
- 1 7 7
180
+ 20 + 100
177 200 300
+ 3
180 335330
+ 5+ 30
Counting up can also be used with 3 digit numbers, for example: 335 – 177 = 158. Firstly, using a number line:
Then usingthe columnmethod:
3 3 5
3
- 1 7 7
180
2 0 200
+ 20 + 100
177 200 300
+ 3
180 335330
+ 5+ 30
Counting up can also be used with 3 digit numbers, for example: 335 – 177 = 158. Firstly, using a number line:
Then usingthe columnmethod:
3 3 5
3
- 1 7 7
180
2 0 200
1 0 0 300
+ 20 + 100
177 200 300
+ 3
180 335330
+ 5+ 30
Counting up can also be used with 3 digit numbers, for example: 335 – 177 = 158. Firstly, using a number line:
Then usingthe columnmethod:
3 3 5
3
- 1 7 7
180
2 0 200
1 0 0 300
3 0
+ 20 + 100
177 200 300
+ 3
180 335330
+ 5+ 30
330
Counting up can also be used with 3 digit numbers, for example: 335 – 177 = 158. Firstly, using a number line:
Then usingthe columnmethod:
3 3 5
3
- 1 7 7
180
2 0 200
1 0 0 300
3 0
+ 20 + 100
177 200 300
+ 3
180 335330
+ 5+ 30
330335 5
Counting up can also be used with 3 digit numbers, for example: 335 – 177 = 158. Firstly, using a number line:
Then usingthe columnmethod:
3 3 5
3
- 1 7 7
180
2 0 200
1 0 0 300
3 0
+ 20 + 100
177 200 300
+ 3
180 335330
+ 5+ 30
330335 5
1 5 8
As with 2 digitnumbers, theamount ofsteps canbe reduced:
3 3 5
- 1 7 7
As with 2 digitnumbers, theamount ofsteps canbe reduced:
3 3 5
2 3
- 1 7 7
200
As with 2 digitnumbers, theamount ofsteps canbe reduced:
3 3 5
2 3
- 1 7 7
200
1 3 5 335
As with 2 digitnumbers, theamount ofsteps canbe reduced:
3 3 5
2 3
- 1 7 7
200
1 3 5 335
1 5 8
That’s it for now......For more help with your maths, try my book:
mastering multiplication tableson amazon.com
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