## What you need to know

**Things to remember:**

- Break up the numerals into parts and change each part into numbers

Where we use 10 numbers to make up all other numbers, the Romans used a combination of 7 letters to write theirs. We have previously just looked at 5 of these, but here we will look at all 7

Roman Numerals I V X L C D M

Numbers1 1 5 10 50 100 500 1000

We previously learned about an important rule, that if there is an I before a V or an X, we subtract 1.

IV

5-1=4

IX

10-1=9

We do something similar with a C before a D or an M, but instead of subtracting 1 we subtract 100.

CD

500-100=400

CM

1000-100=900

Now that we know these, we can put this together with the previously rule we learned about converting Roman numerals into numbers.

**What is DLXIV in numbers?**

D = 500

L = 50

X = 10

I = 1

V = 5

Now we need to add these together. But we need to be careful, the 1 before the 5 means that we subtract this.

DLXIV = 500 + 50 + 10 + 5 -1 = 564

**What is DCCCXXXVIII in numbers?**

D = 500

C = 100

C = 100

C = 100

X = 10

X = 10

X = 10

V = 5

I = 1

I = 1

I = 1

We don’t have any smaller numbers before big numbers, so we can just do lots of adding!

DCCCXXXVIII = 500 + 100 + 100 + 100 + 10 + 10 + 10 + 5 + 1 + 1 + 1 = 838

**What is 495 in roman numerals?**

**Step 1: **Figure out how to write the hundreds, tens, and units in roman numerals.

400 = CD

90 = XC

5 = V

**Step 2: **Put everything together.

495 = CDXCV

**What is 678 in roman numerals?**

**Step 1: **Figure out how to write the hundreds, tens, and units in roman numerals.

600 = DC

70 = LXX

8 = VIII

**Step 2: **Put everything together.

678 = DCLXXVIII

## KS2 SATs Flash Cards

(43 Reviews) £8.99## Example Questions

**Question 1:** What is DCXXXIX in numbers?

D = 500

C = 100

X = 10

X = 10

X = 10

I = 1

X = 10

We have a 1 before a 10, so we need to subtract this and add everything else.

DCXXXIX = 500 + 100 + 10 + 10 + 10 + 10 – 1 = 639

**Question 2:** What is 888 in roman numerals?

**Step 1: **Figure out how to write the hundreds, tens, and units in roman numerals.

800 = DCCC

80 = LXXX

8 = VIII

**Step 2: **Put everything together.

888 = DCCCLXXXVIII

## Times Table Flash Cards

(30 Reviews)- All of the KS2 times tables are covered
- Engaging and fun maths cards

- An easy way to learn
- 1 to 12 - all colour coordinated