New Roman Numerals

How to write 4000 in Roman Numerals?

There is no "unique symbol" for 5000 (or higher multiples) in Roman Numerals. The current convention is that a Roman numeral with a bar above or below means 1000x that number, so 5000 would be V (and technically, 1000 would be I instead of M).

An alternative would be to have another symbol represent 5000 (and so on for 10,000; 50,000; etc.). Though this is highly unlikely to happen, here is what I would propose for the first 3 additional symbols:

1	I
5	V
10	X
50	L
100	C
500	D
1000	M
5000	Y
10000	K
50000	H

So, with my new symbols, 4000 = MY