Bitesize maths addition & subtraction

Bitesize maths

Addition & subtraction

• ​increase confidence with numbers for those needing the first steps towards formal numeracy qualifications  

• practice addition and subtraction

• to recognise how we use addition & subtraction in everyday life 

​Learning objectives

Open Ended

Why have you chosen to do this course?

Multiple Select

How will doing this course help you to progress?

• Employment

• volunteering

• further learning

• Other

Open Ended

Do you feel you need additional support to complete this course?

Poll

How confident do you feel using +/- on a scale from 1-4

• 1

• 2

• 3

• 4

Poll

How familiar are you with the different names of +/-

• 1

• 2

• 3

• 4

Poll

How confident are you counting in 2s, 5s and 10s?

• 1

• 2

• 3

• 4

What is addition?

Addition in the simplest form is taking two numbers and adding them together. The symbol used to show addition is the + (plus symbol).

For example: 1 + 1 = 2

​Examples:

​Similarly,

3 Fishes added to 2 fishes makes 5 fishes

3 + 2 = 5

Open Ended

Can you think of other names of addition?

​Strategies for addition

Using visual objects to add (ADDITION – GeoGebra)

​Other names for addition

​Number line

• ​A straight line on which numbers are marked at equal intervals.

• Number lines are straight lines with numbers evenly spaced in order along the line.

• Numbers increase when moving right on a number line. Numbers decrease when moving to the left.

• Integers, decimals, and fractions can all be labelled on a number line. ( Integer - Any of the positive or negative whole numbers including zero).

​A number line can be used for adding and subtracting by counting on or back

​Open number line beginning skills

​Examples

​Practice the simple questions

​6+4 =

​2+5 =

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​ Using an open number line

For example: 17 + 38

​The number line begins at 0. It then adds the 10 from the first number (17) and then it adds the 30 from the second number (38) which is 3 tens.

As you can see, the arrow has landed on 40. We have now added the tens together.

The next step it to add the ones together: 7 + 8 = 15.

15 is then counted on the number line which takes us to the answer of 55.

In this example, we have partitioned the numbers into tens and ones and added them together to get our end result. 

​Column method without regrouping

• Write the numbers underneath each other

• Add the ones

• Add the tens

​T O

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​Column method with regrouping

T O

T O

​Step 1

​Step 2

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​Strategy 3 - Expanded column

​Step 1: Start from the right side and add the problem in the ones column. In this example its 6 + 3 = 9

​Step 2: Add the tens from both numbers. In this example its 30 + 20 = 50

​Step 3: Combine your solution from ones and tens.

​Other way of using column method

Step 1:​Break the numbers into ones and tens.

Step 2:​Add the number in the ones column 6 + 5 = 11.

Now, you break apart the 11 into tens and ones. write the 1 into ones column (answer column) and carry the 10s to the tens column above the 40.

Step 3:​Add the numbers in the tens column, do not forget to add the 10s carried from ones column.

​Step 4: Combine the solutions

Multiple Choice

What is the total of 36 and 32?

• 64

• 86

• 46

• 68

Multiple Choice

What is the sum of 26 and 31?

• 57

• 39

• 93

• 55

Multiple Choice

• 80

• 90

• 810

• 800

Multiple Choice

• 74

• 47

• 84

• 48

Open Ended

The number in each hexagon is the total of the two numbers below it. Fill in the missing numbers in the empty hexagons.

Write your answers in rows such as 2,5,9,...

​What is subtraction?

​Subtraction is the process of finding the difference between two numbers.

What is subtraction? - BBC Bitesize

​Other words we can use for subtraction

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​Strategies for subtraction

​Column method without regrouping

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​Column method with regrouping

Ones column is 3-6

6 is bigger than 3

so we will borrow one 10 from tens column.

There are 3 10s in tens column.

When we borrow 1, there are 2 10s left.

Ones column becomes 13 as 10+3= 13

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Multiple Choice

10-2 =

• 8

• 7

• 6

• 5

Multiple Choice

10 - 1 =

• 10

• 9

• 8

• 7

Multiple Choice

9-6=

• 2

• 4

• 3

• 5

Multiple Choice

11-2=

• 8

• 7

• 7

• 9

Multiple Choice

15-7=

• 7

• 9

• 8

• 10

Multiple Choice

13-5=

• 9

• 7

• 8

• 6

Multiple Choice

34 + 77

• 111

• 101

• 112

• 102

Multiple Choice

24 - 9

• 16

• 15

• 18

• 12

Multiple Choice

88 + 67

• 155

• 145

• 154

• 144

Multiple Choice

100 - 75

• 20

• 21

• 50

• 25

​Practice questions

Poll

How confident do you feel using +/- on a scale from 1-4

• 1

• 2

• 3

• 4

Poll

How familiar are you with the different names of +/-

• 1

• 2

• 3

• 4

Poll

How confident are you counting in 2s, 5s and 10s?

• 1

• 2

• 3

• 4

Multiple Select

Have you been able to develop in any of the following as a result of today

• English

• Maths

• Employability skills