Question

Express the given Roman number XLIX in English numeral.
A. 69
B. 49
C. 89
D. 59

Answer 1

Hint: Let's break the roman numbers into small parts and then change them to English numerals to find the numeral of XLIX. So, let us make the roman number table for different English numerals.

Complete step-by-step solution:
As we know that XLIX is written in Roman numbers, so let us make a roman number table for different numbers.

English Numeral	Roman Numbers
1	I
5	V
10	X
50	L
100	C
500	D
1000	M

Now each roman number can occur only maximum of three times consecutively. Like III is possible and is equal to 3 but IIII is not possible and is not equal to 4.
And if there are two different roman numbers placed consecutively then if a smaller roman number is on the right of the larger number then the equivalent number will be larger plus smaller (example VI is equal to 6).
And if the smaller is on the left of the larger then the equivalent number will be larger minus smaller (example IV is equal to 4).
So, now let us find the English numeral of XLIX.
As we can see from the above table that L is equal to 50.
And X is on the left of the L. So, XL will be 50 – 10 = 40.
Now IX is on the right of the XL. And in IX as we know that I is smaller and equal to 1 and is on the left of X. So, IX is equal to 10 – 1 = 9.
Now IX is on the right side of XL and is smaller than XL. So, XLIX is equal to 40 + 9 = 49.
So, the English numeral of XLIX is 49.
Hence, the correct option will be equal to B.

Note: If any roman number is such that there are four consecutive same numbers present in it then the number will not be valid like XXXX is not equal to 40 rather 40 is written as XL. So, first we had to find the largest roman numeral letter in the given number like in LDXI first we find that D is equal to 500 and then we had to find the second largest roman letter that is L which is equal to 50 and then L is on the left of D. So, LD will be equal to 500 – 50 = 450. And then we find that X is equal to 10 and I is equal to 1 which is on the right of X. So, XI is equal to 11 and XI is on the right of LD. So, overall number LDXI will be equal to 450 + 11 = 461. This is the efficient way to find the English numeral of a given roman number.