XLV Roman Numerals

What is XLV in Roman Numerals?

The Roman numeral XLV is equal to the number 45. This is one of those Roman numerals where it looks quite straightforward to convert into a modern-day number as it is comprised of individual letters. However, the need for the subtractive principle, where a small number is subtracted from a larger one, complicates the issue of working out what number XLV corresponds to.

We can see that the first two letters of the Roman numeral are XL. Because X = 10 and L = 50, we have to subtract 10 from 50. This is because the smaller number, in this case 10, is written before the larger one, 50. Doing so, we get the number 40.

Now that we have determined that the first part of the number, the second part is easy, as it is just 5 (V). Putting them both together, we get the number 45.

Math Questions Containing the Roman Numeral XLV

Why not have a go at the below math questions to test your knowledge of Roman numerals? Each of the questions contain the Roman numeral XLV in them somewhere.

$A math question being asked in a classroom$

1. What is XLV plus MMXXI?

Hmm, not a very simple one to begin with! We know that XLV = 45, but that second one looks a bit long and difficult, doesn’t it?

In actual fact, there are no smaller numbers before bigger ones, so although there are five letters, they just all need adding together.

The Roman numeral letters that we need to know for solving this equation are:

M = 1,000
X = 10
I = 1

Now all we have to do is add them all together. So, the sum becomes:

1,000 (M) + 1,000 (M) + 10 (X) + 10 (X) + 1 (I) which equals 2021. If the Roman numeral MMXXI looked a bit familiar to you, it’s probably because you’ve seen it on the credits at the end of some of your favorite TV episodes or movies that were made in the year 2021!

2. What is LVI minus XLV?

Not too easy but not too hard this one, as we already know what number each of the letters represents. Plus, of course, we know from the very beginning of this page that XLV equals 45, so we’re already half way there! We just need to calculate what LVI is.

We know that L = 50, V = 5 and I =1, and because LVI does not contain any smaller numbers preceding a larger one, we simply need to add the three letters together. Therefore, the sum is just:

50 (L) + 5 (V) + 1 (I) = 56.

Now that we know what both Roman numerals in the question are, we can subtract 45 (XLV) from 56 (LVI) to give us the answer that we’re looking for, which is 11 (or XI in Roman numerals).

3. What is XLV divided by V?

After the calculations required above, question three is a nice and easy one that won’t be too taxing on the brain!

All it takes to find the answer is to divide 45 (XLV) by 5 (V), which gives us the answer of 9 which is IX in Roman numerals. There, job done and move on to the next one!

4. What is CLXXX divided by XLV?

This final question contains a Roman numeral that we haven't seen up to this point on this page, the letter C. In Roman numerals, C = 100, and because we already know what L and X mean (50 and 10 respectively), then we can see that there is no need to subtract anything when converting CLXXX.

It is therefore simply a matter of adding them together:

100 (C) + 50 (L) + X (10) + X (10) + X (10) which equals 180.

Now that we know CLXXX is 180, we need to divide it by 45 (XLV), to get the answer to the question, which is 4 (or IV in Roman numerals).

Related Page: IV or IIII? - Roman Clock Numerals