1 Addition
57 Models for addition Combining two sets of objects (aggregation) 2
57 Models for addition Combining two sets of objects (aggregation) 3
57 Models for addition Combining two sets of objects (aggregation) 4
57 Models for addition Combining two sets of objects (aggregation) 5
57 Models for addition Adding on to a set (augmentation) Counting on with a bead bar/number line Combining two sets of objects (aggregation) 12 Issue: Tend to count one set, count the other and then count all Issue: Requires fluency with counting from any number Issues: Bead bar is a useful bridge from cardinal to ordinal. Number line helps to stop counting all Also: Bead bar and number line (showing 10s) encourages use of number bonds and place value for added efficiency
More than single digits? 7
8
9
10
11
12
13
14
10 TensOnes
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10 TensOnes
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25 Subtraction
12 Models for subtraction Removing items from a set (reduction or take-away) = 7 Issue: Relies on ‘counting all’, again. Comparing two sets (comparison or difference) Issue: Useful when two numbers are ‘close together’, where ‘take-away’ image can be cumbersome Seeing one set as partitioned Seeing 12 as made up of 5 and 7 Issue: Helps to see the related calculations; 5+7=12, 7+5=12, 12-7 = 5 and 12-5=7 as all in the same diagram N.B. When this is done on a bead bar, there are links with both counting back and difference on a number line 26
Models for subtraction Counting back on a number line Finding the difference on a number line Issue: Number line helps to stop ‘counting all’. Also: Knowledge of place value and number bonds can support more efficient calculating Issue: Useful when two numbers are ‘close together’, use of number bonds and place value can help
More than single digits? 28
This is now “Sixty- twelve”
= 25 33
10 1 TensOnes
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Addition and Subtraction: Both Ways
10 1 TensOnes
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10 TensOnes
10 TensOnes
10 TensOnes
10 TensOnes
10 TensOnes
10 TensOnes
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10 TensOnes
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