Aptitude Numerical series Wipro

Numerical series tests are a type of numerical aptitude test which require you to find the missing number in a sequence. This missing number may be at the beginning or middle but is usually at the end.

Identify the missing number in the series.
	A	B	C	D	E
1) 4, 8, 16, 32, ?	48	64	40	46	44
	A	B	C	D	E
2) 4, 8, 12, 20, ?	32	34	36	38	40
	A	B	C	D	E
3) 54, 49, ?, 39, 34	47	44	45	46	42
	A	B	C	D	E
4) ?, 19, 23, 29, 31	12	15	16	17	18

These number sequences can be quite simple like the examples above. However, you will often see more complex questions where it is the interval between the numbers that is the key to the sequence.

Identify the missing number in the series.
	A	B	C	D	E
5) 3, 6, 11, 18, ?	30	22	27	29	31
	A	B	C	D	E
6) 48, 46, 42, 38, ?	32	30	33	34	35

These numerical series test questions usually consist of four visible numbers plus one missing number. This is because the test designer needs to produce a sequence into which only one number will fit. The need to avoid any ambiguity means that if the number sequence relies on a more complex pattern then there will need to be more visible numbers. For example;

Identify the missing number in the series.
	A	B	C	D	E
7) 4, 3, 5, 9, 12, 17, ?	32	30	24	26	22
	A	B	C	D	E
8) 5, 6, 7, 8, 10, 11, 14, ?, ?	19	17	15	16	21
	A	B	C	D	E
9) 1, ?, 4, 7, 7, 8, 10, 9, ?	6	3	11	13	12

Answers
1. B – The numbers double each time
2. A – Each number is the sum of the previous two numbers
3. B – The numbers decrease by 5 each time
4. D – The numbers are primes (divisible only by 1 and themselves)
5. C – The interval, beginning with 3, increases by 2 each time
6. B – The interval, beginning with 2, increases by 2 and is subtracted each time
7. D – Each number is the sum of the previous and the number 3 places to the left
8. C A – There are 2 simple interleaved sequences  5,7,10,14,19 and 6,8,11,15
9. A D – There are 2 simple interleaved sequences  1,4,7,10,13 and 6,7,8,9