This is an alternating addition series that adds 5, then 2, then 5, and so on.

Here, there are two alternating patterns. The first begins with 17 and adds 2; the second begins with 32 and subtracts 3.

Two patterns alternate here. The first pattern begins with 10 and adds 2 to each number to arrive at the next; the alternating pattern begins with 34 and subtracts 3 each time.

This is a simple addition series with repetition. It adds 3 to each number to arrive at the next, which is repeated before 3 is added again.

In this simple subtraction with repetition series, each number is repeated, then 3 is subtracted to give the next number, which is then repeated, and so on.

The letters decrease by 1; the numbers are multiplied by 2.

This is an alternating division and addition series: First, divide by 2, and then add 8.

This is a simple alternating addition and subtraction series. The first series begins with 8 and adds 3; the second begins with 43 and subtracts 2.

In this series, 5 is added to the previous number; the number 70 is inserted as every third number.

This is a simple addition series; each number is 3 more than the previous number.