**Types of Letter Series:** Some of the important types of series are given below.

**Addition Series:** In this type of series, a number is added to the previous letter to get the next letter. The number which is added can be the same for the whole series or in a certain order.

**Example(1):** What will come in the place of question mark (?) in the given series?

**A, B, D, G, K, ?**

**Answer:**

In the given series the difference between two consecutive letters is in the increasing order. In this series, the numbers 1, 2, 3, and 4 are added to the previous letter respectively, to get the next letter.

**Example(2):** What will come in the place of question mark (?) in the given series?

**A, C, E, G, I, ?**

**Answer:**

In the given series the difference between two consecutive letters is same. In this series, 2 is added to the previous letter respectively, to get the next letter.

**Subtraction Series:** In this type of series, a number is subtracted from the previous letter to get the next letter. The number which is subtracted can be the same for the whole series or in a certain order.

**Example(1):** What will come in the place of question mark (?) in the given series?

**J, H, F, D, ?**

**Answer:**

In the given series the difference between two consecutive letters is same. In this series, 2 is subtracted from the previous letter respectively, to get the next letter.

**Example(2):** What will come in the place of question mark (?) in the given series?

**K, J, H, E, ?**

**Answer:**

In the given series the difference between two consecutive letters is in the increasing order. In this series, the numbers 1, 2, 3, and 4 are subtracted from the previous letter respectively, to get the next letter.