Institute of Banking and Personnel Selection (IBPS) will conduct common written examination for recruitment of Specialist Officers (SO). The IBPS SO Exam will be conducted in the last week of January 2016.

The banking team of jagranjosh.com has brought concept and sample questions for Number series (Quantitative Aptitude). The concept provided by us will help you to understand the topic. The sample questions offered by us are framed by keeping in view need of the question paper.

*Type *1 **To Find the Missing Term**

**Directions (Q. Nos. 1 to 2):** Find the missing term in each oy the following number series.

**Example 1** 13, 18, 16, 21, 19, 24,?

**Solution:** Clearly, the given series follows the pattern +5, -2, +5, -2, …….

So, Missing term = 24 – 2 = 22

**Example 2** 3333, 3233, 3143, 3063,?

**Solution:** Clearly, the given series follows the pattern -100, -90, -80, -70, ………

So, Missing term = 2993

**Triangular Pattern Series **

In such a series, the difference between the consecutive terms of a series, again form a series. The difference between the consecutive terms of the new series so formed again forms a series. This pattern continues till we attain a constant difference between the consecutive terms of the series.

**Example 3** 4, 18, 48, 100, 180, 294,?

**Solution: **

So, the missing term = 34 + 6 = 40

Then, 40 + 114 = 154 and 294 + 154 = 448

*Type 2 ***To Pick the Odd One **

**Directions (Q. Nos. 5 to 6):** In each of the following number series, one of the given numbers is wrong. Find out the number.

**Example 4** 2, 7, 14, 23, 36, 47, 62

**Solution: **Clearly, the correct sequence is 2^{2} - 2, 3^{2} - 2, 4^{2} - 2, 5^{2} - 2, 6^{2} - 2, 7^{2} - 2, 8^{2} - 2.

So, 36 is wrong and should be replaced by (6^{2} -2) =34

**Example 5** 1, 27, 125, 343, 729, 1321

**Solution: **Clearly, the correct sequence is 1^{3}, 3^{3}, 5^{3}, 7^{3}, 9^{3}, 11^{3}

So, 1321 is wrong and should be replaced by 11^{3} = 1331