History of Calculation Grid
A number puzzle of calculations in rows and columns, related to the ancient magic square of the numbers 1 to 9.
The magic square
The best-known number puzzle with the numbers 1 to 9 in a 3 × 3 grid is the magic square, in which every row, column and diagonal adds up to 15. In China it is known as the Lo Shu (Luoshu) and is tied to a legend about a turtle. How old it really is remains unclear: the dates given in the sources lie far apart.
Calculations in rows and columns
Calculation Grid keeps the 3 × 3 grid with the numbers 1 to 9, but asks for a different calculation in every row and column. Puzzles of this kind appear in school workbooks and puzzle collections, partly with the usual order of operations. Where this form first appeared, PaperGames could not find out; the name Calculation Grid is a plain description.