Drag counters into the board. Each counter adds to the total.
Red counters show the numeral that is subtracted from the blue numeral.
How Roman Numerals Work
Roman numerals use letters instead of digits to show numbers.
- I means 1
- V means 5
- X means 10
- L means 50
- C means 100
- D means 500
- M means 1,000
If a smaller numeral comes
before a bigger one, you
subtract it.
For example:
- IV = 4 (one before five)
- IX = 9 (one before ten)
- XL = 40 (ten before fifty)
If a smaller numeral comes
after a bigger one, you
add it.
For example:
- VI = 6 (five plus one)
- XI = 11 (ten plus one)
- XV = 15 (ten plus five)
Try using the counters to build numbers and see how the Roman numerals are made!