Can't enter a number into my speadsheets

Moves me to a different cell using 3.6. When I try to enter a number into a spreadsheet cell, the cursor moves to a different cell.

Can’t figure what to do. Used to work.

(edited by ajlittoz: transferred from the title to the question to make it shorter and the question more self-sufficient)

using 3.6.

really that old one?


`NUM` off? - check your numpad