Rearrange the same set of numbers in every row and column so each line, worked out with BODMAS, makes its total.
The full guide, with a worked example and common mistakes: How to play Number Order.
Yes — every puzzle is checked, and locked tiles are added where needed to make it unique.
From level 5 (Expert) the signs can be swapped within their row or column too.
A power: 2 ^ 3 = 2 × 2 × 2 = 8. It is worked out before × and ÷. Powers appear on the Genius level.