In mathematics, numbers are often arranged in a sequence.
Often a sequence follows a rule or pattern.
Some sequences are obvious: 2, 4, 6, 8, 10...
The formula for this sequence is 2n where n stands for a counting number.
To find the next number in this sequence, calculate 2 x 6 = 12
Slightly Harder Sequence
The sequence 1, 4, 9, 16, 25... is the sequence of square numbers.
The formula for this sequence is n2.
More Difficult Sequence
The number of diagonals in polygons forms a sequence.
The sequence for the number of diagonals is 0, 2, 5, 9, 14...