I have a Mac mini with High Sierra (10.13.4) with a Windows-keyboard (it has a numpad).
Everything went fine for a long time but a few months ago I got a big problem: In many apps (Calculator, Excel, etc.) when I want to write for example "567" with the numpad, the number I push overwrites the last number. So if I push 5, 6 and 7, than instead of "567" it just shows a 7 (because the 6 overwrites the 5, and the 7 overwrites the 6).
In some apps however it works fine, for example in TextEdit or Firefox...
I probably just pushed some keyboard-shortcut which made this issue, but it really makes me go crazy. Could you please help me?
Thank you very much!