Consecutive numbers are ones that follow on from each other in order, like 2, 3, 4 and 5. We can create certain numbers by adding together runs of consecutive numbers, e.g. 1 + 2 + 3 = 6 or 14 + 15 = ...

Find one million consecutive positive numbers, none of which are prime. Ancient math tells us that prime numbers (2, 3, 5, 7, 11, ...,), which have no factors except for 1 and themselves, go on ...