First of all let me clarify that what you are solving in the Civil Service Examination are number sequences (or letter sequences) and not a number series. A series has a different meaning in mathematics.
Before proceeding with the discussion below, first, try to find the next term in the following sequences.
1. 4, 7, 10, 13, ___
2. 17, 11, 5, -1, ___
3. C, F, I, L, ___
4. , , , .
Solution and Explanation
Numbers 1 and 2 are the easiest type of sequence to solve. This is because they are integers and you just add (or subtract) a constant number to each term to get the next term. In solving this type of sequence, you can see this pattern by subtracting adjacent terms (13 – 10 = 3, 10 – 7 = 3, 7- 4 = 3) to see if the difference is constant. If it is, then you will know that you will just have to add the same number to get the next term. Therefore, the next term to the first sequence is 13 + 3 = 16. Continue Reading