Calcuku's (also known as Hitoshii and a few more) are sudokus where you have to calculate.
Rows and columns are home to numbers 1..4, 1..5, 1..6 or 1..9 (the most used) although for
this program it makes no differencce, sizes 4 by 4 up to 9 by 9 are allowed.
The calcudoku/py program is converted from the BASIC example to python3, if you have installed
python39 (from !Packman) just enter python3 calcudoku/py (that is, if calcudoku/py is in the
current directory, other make it the current directrory (filer-->Menu, click Set directory)
or adapt the path in the python3 call. Alternatively, give calcudolu/py filetype a73 or Python3.
This calcudoku.py program also runs under Linux and maybe other OS-es, bytheway.

First, enter the dimension.  4 up to 9.

Then, enter the operator (+.-,* or /)  or '=' for setting a value to one cell. Or 'v' for an example.
Immediately after this, the value. E.g. when the cells in a group add up to 16, do '+16 '
Or if they multiply to 144, do '*144 '. Allowable tokens are + - * X / : =
Ror addition, subtraction, multiplication, division, direct value.
After this, a space and then the cell numbers that belong to this group, all separated by spaces.
Not by commas. 

'D' or 'd' can be used to delete the previous group.
It does not do a lot of harm to re-type-in a group or groups if you made a mistake. The order of how 
you type in the groups or the cells inside those groups also is unimportant. 
If all the data are typed-in the program starts to calculate. Because of the optimisations 
it's not overly slow, although it only uses a try-and-backtrace-if-failed method. 
So it definitely is a dumb program, but small. The result can be exported as a textfile, which
should be, with a non-proportional font, more or less readable.
'V' or 'v' (='voorbeeld') can be used at the start to print an example.

To get a taste: 
(Dimension) 4
-1 0 4
+9 1 2 3
+8 5 6 7
+11 9 0 12
+4 10 13 14
-1 11 15