In Year 6, the fourth year in KS2 and the last before secondary school, children will come across ever more difficult addition and subtraction problems in Maths. They will be expected to understand different terms describing addition and subtraction, such as altogether, difference, increase and decrease.

The ability to work out addition and subtraction problems is very important in all walks of life. It's used when stock-taking for example. A bakery has 100 iced buns and sells 60 by lunchtime. In the afternoon a customer requests 38 iced buns for a party. The baker needs to know whether she has enough buns left so she must be able to work out the answer. Or you might want to work out the year in which your grandmother was born. If she is 60 years old then you can take 60 from the current year to get the answer. Both of these are examples of addition and subtraction problems.

Have a go at the following Year 6 quiz and find out how much you know about addition and subtraction.

1.

What is the best method of adding 0.9?

Add 1 subtract 1

Add 1 add 0.1

Subtract 1 subtract 0.1

Add 1 subtract 0.1

2.

How many altogether are 258 and 162?

320

400

420

450

One way to work this out is to add the units: 2 + 8 = 10

then the tens: 50 + 60 = 110

then the hundreds: 200 + 100 = 300

then add them all together: 300 + 110 + 10 = 420

then the tens: 50 + 60 = 110

then the hundreds: 200 + 100 = 300

then add them all together: 300 + 110 + 10 = 420

3.

What is the difference between 6.3 and 2.4?

2.9

3.9

4

4.1

Difference means take the smaller number away from the larger

4.

What is the best method of adding 34 + 48 + 56?

Find the pair that total a multiple of 100 - add these first

Find the pair that total a multiple of 10 - add these first

Add 10s first then the units

Double 34 then adjust

34 + 56 = 90 which is a multiple of 10 now add 48 so 90 + 48 = 138

5.

Which strategy would be best to add 69 + 61 + 65 + 67?

(60 x 4) + (1 + 5 + 7 + 9)

(70 x 4) - (1 + 5 + 7 + 9)

(61 + 65) + (67 + 69)

(60 x 4) - (1 + 5 + 7 + 9)

60 x 4 = 240 and 1 + 5 + 7 + 9 = 22

240 + 22 = 262

240 + 22 = 262

6.

Decrease 2.5 by 1.8.

0.6

0.7

1.7

4.3

Decrease means get smaller so we subtract the numbers

7.

Which of these number sentences is incorrect?

2.56 + 3.41 = 5.97

5.97 - 3.41 = 2.56

5.97 - 2.56 = 3.41

3.41 - 2.56 = 5.97

3.41 - 2.56 = 0.85

8.

Increase 450 by 230.

220

280

580

680

Increase means get larger so we add the numbers

9.

Which strategy would be best to subtract 2.9?

Add 3 subtract 1

Subtract 3 add 0.1

Subtract 3 subtract 0.1

Subtract 3 add 1

e.g. 3.4 - 2.9:

3.4 - 3 = 0.4

0.4 + 0.1 = 0.5

so 3.4 - 2.9 = 0.5

3.4 - 3 = 0.4

0.4 + 0.1 = 0.5

so 3.4 - 2.9 = 0.5

10.

Which of these pairs would not make a whole number?

2.78 + 0.22

3.54 + 2.46

5.01 + 1.9

4.97 + 2.03

5.1 + 1.9 = 7 but 5.01 + 1.9 = 6.91 which is not a whole number

1.3 + 1 = 2.3

2.3 - 0.1 = 2.2

so 1.3 + 0.9 = 2.2