Welcome to the second of our easy Eleven plus maths quizzes on Number Sequences. These are slightly trickier than our very easy ones so, if you haven’t played those already, why not give them a try? They give you a gentle introduction to the topic.

If you have played the previous quizzes then you’ll know that a number sequence is a series of numbers which follow a rule. The difficult part is finding the rule: you may have to add or subtract a certain number, or multiply or divide by another. Sometimes it’s not so easy – you might have to add 1, then 2, then 3 etc. or you could be squaring the previous number.

Trial and error is the best way to tackle these. Speaking of which, it’s time to try the ten questions which follow – and let’s hope you don’t make any errors!

1.

Find the missing term.

0, 1, 3, 6, 10, X, 21, 28, ...

0, 1, 3, 6, 10, X, 21, 28, ...

14

15

16

17

The terms of this sequence are triangle numbers. These are made by starting with 0, then adding 1, next add 2, then add 3 etc.

2.

Find the missing term.

200, 100, 50, 25, X, ...

200, 100, 50, 25, X, ...

15

12.5

10

7.5

The next term is got from the previous term by dividing by 2 , e.g. 200 ÷ 2 = 100 and so on.

As I am sure you know, dividing by 2 is the same as multiplying by^{1}⁄_{2}

As I am sure you know, dividing by 2 is the same as multiplying by

3.

Find the missing term.

43, 26, 9, X, ...

43, 26, 9, X, ...

3

0

-4

-8

The next term is got from the previous term by subtracting 17, e.g. 43 - 17 = 26 and so on

4.

Find the missing term.

60, 20, 6^{2}⁄_{3}, X, ...

60, 20, 6

1^{8}⁄_{9} or 1.888

2^{1}⁄_{9} or 2.111

2

2^{2}⁄_{9} or 2.222

The next term is got from the previous term by dividing by 3, e.g. 60 ÷ 3 = 20 and so on. You may have needed to use your calculator.

Of course, dividing by 3 is the same as multiplying by^{1}⁄_{3}

Of course, dividing by 3 is the same as multiplying by

5.

Find the missing term.

7, 29, 51, 73, X, ...

7, 29, 51, 73, X, ...

95

97

99

101

The next term is got from the previous term by adding 22, e.g. 7 + 22 = 29 and so on

6.

Find the missing term.

14, 23, 32, X, ...

14, 23, 32, X, ...

39

40

41

42

The next term is got from the previous term by adding 9, e.g. 14 + 9 = 23 and so on

7.

Find the missing term.

4, 1,^{1}⁄_{4}, X, ...

4, 1,

The next term is got from the previous term by multiplying by ^{1}⁄_{4}, e.g. 4 × ^{1}⁄_{4} = 1 and so on.

Multiplying by^{1}⁄_{4} is the same as dividing by 4

Multiplying by

8.

Find the missing term.

-11, -4, X, 10, ...

-11, -4, X, 10, ...

3

2

1

0

The next term is got from the previous term by adding 7, e.g. -11 + 7 = -4 and so on

9.

Find the missing term.

6, 2,^{2}⁄_{3}, X, ...

6, 2,

0

The next term is got from the previous term by multiplying by ^{1}⁄_{3}, e.g. 6 × ^{1}⁄_{3}, = 2 and so on.

Multiplying by^{1}⁄_{3} is the same as dividing by 3. You may have needed to use your calculator for this one!

Multiplying by

10.

Find the missing term.

23, 36, X, 62, ...

23, 36, X, 62, ...

51

50

49

48

The next term is got from the previous term by adding 13, e.g. 23 + 13 = 36 and so on