Adjust cell width and height to fit print margins (no gaps)?

[Harry Geda]

Hello,

I would like to adjust my cell height and width to perfectly fit a margin of:
0.75inch from right and left.
0.50inch from top and bottom.
No room for header or footer.

I have 5 columns and 10 rows per page.
I adjust my printer margins to match the numbers above and center the prints but can not find the magical number that will allow me to fill the 7x10 area perfectly. Either I am short on height or width.

Please advise on how to calculate numbers.
My printed sheet should be 7x10 inch.

Thank you,
Harry

 

[Harry Geda]

Not enough detail or hard topic?
Be brave and answer me.