Look at this series: 2, 4, 6, 8, 10, ... What number should come next?

This is an alternating multiplication and subtracting series: First, multiply by 2 and then subtract 8.

In this simple addition series, each number increases by 0.8.

This is a simple alternating subtraction series, which subtracts 2, then 5.

This is a simple addition series with a random number, 8, interpolated as every other number. In the series, 6 is added to each number except 8, to arrive at the next number.

This alternating addition series begins with 3; then 1 is added to give 4; then 3 is added to give 7; then 1 is added, and so on.

In this addition series, 1 is added to the first number; 2 is added to the second number; 3 is added to the third number; 4 is added to the fourth number; and go on.

This is a simple subtraction series. Each number is 35 less than the previous number.

This is an alternating addition and subtraction series. In the first pattern, 10 is subtracted from each number to arrive at the next. In the second, 5 is added to each number to arrive at the next.

This is a simple multiplication series. Each number is 3 times more than the previous number.

In this simple subtraction series, each number decreases by 0.4.