M = 1,000
D = 500
C = 100
L = 50
X = 10
V = 5
I = 1
MDCCXLIV
M = 1,000
DCC = 500 + 100 + 100 = 700 (smaller after larger, then adding)
XL = 50 - 10 = 40 (smaller before bigger, then subtraction)
IV = 5 - 1 = 4 (smaller before bigger, then subtraction)