XXI
It is: XXI = 21
21 + 22 = 43 = XLIII
The date 09-21-2008 can be represented by the Roman numerals IX.XXI.MMVIII
21 = XXI
XXIXXI = 21
21 = XXI
Ah, isn't that a happy number to work with? To write 21 million in numbers, you simply write 21 followed by six zeros: 21,000,000. Just think of all the happy little zeros dancing around that 21, creating a beautiful number on your canvas of mathematics.
It is a triangular number In Roman numerals = XXI It is the sun of the first 6 numbers (1+2+3+4+5+6=21)
XXI is the number 21 in Roman numerals.
XXI
As a number it is: 21,000
ANY number that you can write as a fraction (with whole numbers top and bottom) is rational.