Convert fractions to decimals within the program, not just the new file dialogue box: 1167/8" to 116.875 in.
We work with various large format sizes given with fractions, but the programs run off decimals. The New file dialogue box will convert them, so why can't this be added to the number fields for artboard and object sizes? Similar to how we can use the "/" to divide by a number when working at 1/4 scale or 1/2 scale.

Natalie Nelson commented
Egor, you can use a space between the whole number and the fraction like 116 7/8. The feature request was to automatically convert the fraction to decimal, not regarding subtraction. I know the number fields work with math, as they already use the "/" symbol to divide. I use that all the time, as we work in extreme large format printing.

Your use a hyphen to type it, don't you? This is treated as a minus generally.
I just want to point out there is a clash between the metric and nonmetric systems once again, and if it gets done that straightforward, this is going to upset a lot of users, who do not care about fractions of an inch.
I understand your frustration as well, I just add there can be even more frustration caused by 'fixing' it.
Am interesting idea though, I wonder if any comments will follow. Thanks for the request! 
Natalie Nelson commented
Hi Egor, it's not a minus, it's what's used to separate the whole number from the fraction. We are working off sizes from Autocad on a daily basis.

While I'm all in for complex math operations in a field, I can't but notice that '1167/8' is '116 minus 7 divided by 8', which gives '115.125'. The division is performed before subtraction, evich is a not even a thing which is universally agreed on — but using a minus sign as a conjunction symbol is even less conventional and intentionally adopted.