Twelve sequences a sheet, each six terms long with one term blanked out. Every sequence moves by a fixed step between 2 and 12, and about half of them count down rather than up - which is the half that catches people out, because a falling sequence is still a pattern even though the arithmetic is subtraction.
A descending sequence is built to finish above zero rather than generated and thrown away if it does not, so no sheet contains a negative term and none of them is a near miss quietly discarded. The blank does not always sit at the end either: it can fall anywhere in the row, so finding the step sometimes means working backwards from the terms on its right.
Work out the step by subtracting one term from the next, then apply it to the term beside the blank. In 4, 11, 18, ___, 32 the step is 7, so the missing term is 25.
Yes, about half of them. A descending sequence is built so its last term is still positive, so the numbers stay whole and above zero all the way along.
No. It can fall anywhere in the row, including the first position, which means reading the pattern from the right as well as the left.
No. Two sequences count as the same problem when their terms match, even if the blank sits in a different place - moving the gap does not make a new question.