Addition and subtraction

Question 1

What are the key words of a sum?

34 + 56 = 90

Answer 1

Addend + Addend = Sum/Total

Question 2

What are the key words of a sum?

45 - 13 = 32

Answer 2

Minuend - Subtrahend = Difference

Question 3

What are the two important categories in addition?

Answer 3

1. Union of two sets - Think about the language – ‘How many altogether?’
2. Counting on and increasing

Question 4

1. Union of two sets - Think about the language – ‘How many altogether?’
2. Counting on and increasing
   Examples?

Answer 4

In pairs discuss the word stories you could make up for 13 + 4 for each category above:
e.g. 13 blue counters and 4 red counters – How many counters are there altogether?
I am on square 13 in snakes and ladders and I throw a 4 on the dice – What square am I on now?

Question 5

What is the name of a structure which involves the union of two sets?

Answer 5

Aggregation structure (combining) so for instance a circle with 4 counters another with 3 counters and then the total 7.

Question 6

What is the counting on and increasing structure called?

Answer 6

Augmentation structure (Number line) like counting on.

Question 7

What is compensating on a number line?

Answer 7

Is when we take away something on a number line.

Question 8

What is the Commutative Law?

Answer 8

a + b = b + a (4 + 5 = 5 + 4)

We cannot use this law for subtraction as it leads to misconceptions, e.g. 9 – 5 = 5 – 9?

Question 9

What is the Associative Law?

Answer 9

a + ( b + c) = (a + b) + c

12 + (6 + 2) = (12 + 6) + 2

Question 10

What are the five key structures of the subtractions?

Answer 10

1. Partitioning – e.g. ‘How many are left?’
2. Comparison – e.g. ‘How many more/less?’
3. Complement of a set
4. Reduction – counting back
5. Inverse of addition

Question 11

What are the partitioning structures?

Answer 11

Take away
How many are left?
https://canvas.wlv.ac.uk/courses/28907/pages/session-4-addition-and-subtraction-1

Question 12

What’s the comparison structure?

Answer 12

‘difference’
Fill the gap… How much older? How much heavier?
(Numberlines?)

Question 13

What is complementary addition?

Answer 13

How many more to make?’

I have 37p but I want to buy some chocolate that is 49p. How much more do I need?

Question 14

What is The Reduction Structure?

Answer 14

Counting back
The chocolate bar was 12p. The shop thought it was too expensive and took 3p off.
Count back (from the correct number), reduce.

Question 15

5. Addition as the Inverse of Subtraction

Answer 15

Key words – undoing and reversing
a - b = c then c + b = a
10 - 7 = 3 then 3 + 7 = 10

Question 16

What are the key terms of subtraction and addition

Answer 16

In addition it’s called the total or the sum

In subtraction its called the difference

Negative numbers

Partitioning both numbers you add them to get the number together.

If subtraction you are only partitioning one number