2000 40 110 57
v.
7, 8, 5, 7



Are you trying for LXXXVI XLVII?

In the second, that would be VIIIVIIVVII (What you wrote is 7747 - VII VII IV VII). I think you've got a misplaced I.

I always hated the Roman way of accounting

to Texas Instruments calculators!!!

The only time I really try to figure it out is the date of publication

Talk about convoluted!

VIIIVIIVVII = VIII VI IV VII = 8 6 4 7 and LXXXVIXLVII = LXXXVI XLVII = 86 47
but MMXDCXLVII = MM X DC XLVII = 2000 10000 600 47

https://www.tuomas.salste.net/doc/roman/numeri-romani.html

See https://www.cuemath.com/numbers/8000-in-roman-numerals/
so
V̅I̅I̅IDCXLVII
or this says you can use M instead of I̅, which is what your source does
https://mammothmemory.net/maths/numbers/roman-numerals/roman-numerals-from-1000-to-1-million.html
V̅MMMDCXLVII