MAT1236 Lecture Notes - Lecture 3: Commutative Property
4 Jun 2018
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Department
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Professor
WEEK$3$
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Additive$thinking,$contexts,$methods,$and$strategies$
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Models$used$to$represent$the$addition$concept$include:$
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Properties$of$addition:$
P Commutative)property)of)addition:)089(+5.95(1-(<81:8(0<+(A+5(6+59B(-,6=952(/59(
/..9.(.+92(-+0(/339:0(089(2,6(A9DE(&Q%(R(%Q&(S(FB(
P Associative)property)of)addition:)089(D5+,?1-D(+3(-,6=952(1-(/..101+-(.+92(-+0(/339:0(
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• Additive)property)of)zero:)/..1-D(Y95+(0+(/-7(-,6=95(.+92(-+0(:8/-D9(089(+51D1-/>(
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Compensation(
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Teaching$mental$strategies$for$addition:$
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Document Summary
The notion of how many or how much altogether". Models used to represent the addition concept include: counters, connecting cubes, a hundred square, a number line, using a balance. Compensation can be used to simplify calculations by temporarily adding or subtracting an appropriate small number. Eg: to find 673 + 99, we could temporarily add 1 to the 99 to make 100, adding 673 + 100 gives 773, and we compensate by removing 1 to get 772. Extend basic facts: since 4+5=9, we also know the 40+50=90 and 400+500=900. Practice counting on: forwards and backwards, from any starting point, skip counting (after. Use compatible or friendly" numbers: add 8+7+22+5+13, we recognise that 8 and 22 are compatible (=30) and 7 and 13 are compatible numbers (=20) Encourage students to develop and explain their own strategies. An algorithm is a step-procedure for performing a calculation. Standard written algorithm: also known as column addition.
