Under today's modern rules now governing the Roman numeral system 249 in Roman numerals is considered to be CCXLIX but the ancient Romans would have probably evaluated the above in any of the following formats:-
A: MDCCLXXVI+ICCL = MMXXV => 1776+(250-1) = 2025
B: MDCCLXXVI+CCXXXXVIIII = MMXXV => 1776+249 = 2025
C: MDCCLXXVI-ICCL = MDXXVII => 1776-(250-1) = 1527
D: MDCCLXXVI-CCXXXXVIIII = MDXXVII => 1776-249 = 1527
QED
See answer to question: ' How do you add together 1666 and 1999 in two different ways using Roman numerals'
Roman numerals are entirely inappropriate for doing such calculations. I believe the people in Roman times did such calculations on an abacus or something similar - which is basically similar to converting them to the Arabic numbers we use. If you really want to do it in Roman numerals - which is basically NOT a good idea - you would have to keep the thousands, hundreds, etc. separate, and handle carry (for addition) and borrowing (for subtraction).
When 9 is converted into Roman numerals it is IX which is an abridged version of VIIII and so the required calculations are as follows:-MDCCLXXVI+IX = MDCCLXXXV => 1776+(10-1) = 1785MDCCLXXVI+VIIII = MDCCLXXXV => 1776+9 = 1785MDCCLXXVI-IX = MDCCLXVII => 1776-(10-1) = 1767MDCCLXXVI-VIIII = MDCCLXVII => 1776-9 = 1767Note that in mathematics -(10-1) changes to 1-10QED
According to my calculations,mccxxix in Hindu Arabic numerals is 1229
The Romans did their calculations on an abacus counting device which was the equivalent to a primitive calculator.
See answer to question: ' How do you add together 1666 and 1999 in two different ways using Roman numerals'
Roman numerals are entirely inappropriate for doing such calculations. I believe the people in Roman times did such calculations on an abacus or something similar - which is basically similar to converting them to the Arabic numbers we use. If you really want to do it in Roman numerals - which is basically NOT a good idea - you would have to keep the thousands, hundreds, etc. separate, and handle carry (for addition) and borrowing (for subtraction).
Since you ask how I would do it: I would forget about doing this in Roman; rather, I would convert everything to arabic numbers, which are much more appropriate for such calculations.
Numerals are used for mathematical calculations. Mathematical calculations are used in science. This is the way Roman numerals related to Roman science.
In today's modern conversion of Roman numerals 49 and 19 are now considered to be XLIX and XIX respectively but the ancient Romans would have probably worked out the above as follows:- IL+IXX = LXVIII => (50-1)+(20-1) = 68 XXXXVIIII+XVIIII = LXVIII => 49+19 = 68 IL-IXX = XXX => (50-1)-(20-1) = 30 XXXXVIIII-XVIIII => 49-19 = 30 For more complicated calculations the Romans would use an abacus calculating device.
When 9 is converted into Roman numerals it is IX which is an abridged version of VIIII and so the required calculations are as follows:-MDCCLXXVI+IX = MDCCLXXXV => 1776+(10-1) = 1785MDCCLXXVI+VIIII = MDCCLXXXV => 1776+9 = 1785MDCCLXXVI-IX = MDCCLXVII => 1776-(10-1) = 1767MDCCLXXVI-VIIII = MDCCLXVII => 1776-9 = 1767Note that in mathematics -(10-1) changes to 1-10QED
According to my calculations,mccxxix in Hindu Arabic numerals is 1229
The Romans did their calculations on an abacus counting device which was the equivalent to a primitive calculator.
Doing arithmetic with Roman numerals is exasperating, and imho a pointless waste of time, except to demonstrate the obvious superiority of our "normal numbers," which use base-10 radix / positional notation that includes a zero digit as a placeholder. I'd venture to say science & technology -- commerce, too -- could never have developed in recent centuries if we still used Roman numerals for calculations. However, this web site explains some methods: http://turner.faculty.swau.edu/mathematics/materialslibrary/roman/
Under today's modern rules now governing the Roman numeral system the equivalent of 249 when converted into Roman numerals is now considered to be CCXLIX which does not lend itself quite easily to arithmetical operations but there exist credible evidence to suggest that the ancient Romans would have carried out the requested calculations as follows:-MDCCLXXVI+ICCL = MMXXV => 1776+(250-1) = 2025MDCCLXXVI+CCXXXXVIIII = MMXXV => 1776+249 = 2025MDCCLXXVI-ICCL = MDXXVII => 1776-(250-1) = 1527MDCCLXXVI-CCXXXXVIIII = MDXXVII => 1776-249 = 1527Note that in mathematics -(250-1) becomes -250+1 or as 1-250The above calculations were fairly simple and straight forward to work out but for more complicated calculations the Romans would make use of an abacus calculating device.QED
They're great for clocks, but try doing basic calculations with them. The Romans had no representation for the number zero. It was the Greeks who invented Zero as a number. Therefore calculations with Roman numerals is extremely difficult.
The rules as we know them today now governing the Roman numerals system had absolutely nothing to do with the Romans because they were introduced during the Middle Ages and as a result of these rules 1999 when converted into Roman numerals is now considered to be MCMXCIX which hardly lends itself quite easily for the purpose of arithmetical operations but notwithstanding the aforementioned inasmuch that there exist credible evidence to support the premiss that the ancient Romans would have worked out the requested calculations as in the following formats:-MDCCCCLXXXXVIIII+MDCCLXXVI = MMMDCCLXXV => 1999+1776 = 3775IMM+MDCCLXXVI = MMMDCCLXXV => (2000-1)+1776 = 3775MDCCCCLXXXXVIIII-MDCCLXXVI = CCXXIII => 1999 -1776 = 223IMM-MDCCLXXVI is the same as the above because IMM = MDCCCCLXXXXVIIIIThe above calculations were fairly simple and straightforward to work out but for more complicated calculations the Romans would have made use of an abacus calculating device.QED