45
X = 10
L = 50
V = 5
A smaller number (letter) in front of a larger one means less or negative. XL = ten less fifty, which is the same as 50-10=40.
Then the smaller numbers after a larger number are added. So plus five for the V.
Add them all up
(50-10)+(5)
Forty Five
You might remember seeing MCMXCVIII on things in 1998.
I = 1
V=5
X=10
C=100
M=1000
(1000)+(1000-100)+(100-10)+5+1+1+1=1998
XLV in Roman numerals = 45
XLV = 45
In todays modern era of notating Roman numerals they represent 1933
MCMXCIV
It is equivalent to 1026 in Roman numerals
XLV in Roman numerals = 45
XLV = 45
In todays modern era of notating Roman numerals they represent 1933
XXVII
MCMLXX
MCMXCIV
XXII.I.MCMXC
It is equivalent to 1026 in Roman numerals
45 but under today's notation of Roman numerals it is written out as XLV
2010 = MMX
CXX
IV