Answer: What Comes Next? #442

The answer is A: 33.

The finished pattern: 12, 13, 15, 18, 22, 27, 33.
The finished pattern.

The rule

Add 1, then add 2, then add 3, then 4… The gap grows by one every time.

The pattern as Python code

Here is a tiny Python program that follows the same rule. Type it into IDLE and run it to print the whole pattern, including the answer.

number = 12
gap = 1
for step in range(7):
    print(number)
    number = number + gap
    gap = gap + 1

When you run it, Python prints:

12
13
15
18
22
27
33

Pixel says: Try changing a number in the code and run it again. Can you make the pattern go on for 20 steps? Meow!