First, look for a pattern. Notice how each number is 3 times the previous number:

1, 3, 9, 27, __, 243

Multiply 27 by 3 to find the missing number:

27 × 3 = 81

To make the pattern complete, the number 81 must go in the blank space.

Look for the pattern. 1, 4, 16, 25, 36, 49 and 64 are all

perfect squares.Rule: The n^th term is n².

You are trying to find the 3^rd term. Plug n=3 into the rule.

n² = 3² = 9

The missing number in the pattern is 9.

The pattern is:

1 4 9 16 25 36 49 64

Find the pattern. Look at how much you add to each number to get the next number:

The amount you add increases by 1 each time. Now you know how much to add to find the missing number:

The missing number is 12.