Convert the Number 21 and Write it With Roman Numerals. Write the Number Using the Roman Numeral System Letters. Learn by Using the Detailed Explanations Converter

Number 21 written in Roman numerals

The Roman numerals that we're going to use to make the conversion:


1. Break down the number.

Decompose the number, break it down into place value subgroups:

21 = 20 + 1;


2. Convert each subgroup.

Convert each of the place value subgroups, write them in Roman numerals:

20 = 10 + 10 = X + X = XX;


1 = I;


3. Wrap up the Roman number.

Put all the components together, construct the Roman number.


Substitute the Roman numerals calculated or listed above for each of the (place value) subgroups of the (Hindu-Arabic) number:


21 =


20 + 1 =


XX + I =


XXI


How to convert the number, how to write it in Roman numerals: 21 = ?

21 written in Roman numerals:
21 = XXI

XXI is a group of numerals written in additive notation.

» The additive notation used in the writing of the Roman numerals


Online converter of numbers to Roman numerals

Learn how to convert numbers to Roman numerals:

Decompose the number, break it down to place value subgroups.

Convert each of the place value subgroups, write them in Roman numerals.

Construct the Roman numeral / Substitute the calculated Roman numerals for each of the place value subgroups of the (Hindu-Arabic) number.

The latest Hindu-Arabic numbers converted to Roman numerals

How to convert: write the Hindu-Arabic number 21 using Roman numerals: XXI Mar 29 05:35 UTC (GMT)
How to convert: write the Hindu-Arabic number 175,433 using Roman numerals: (C)(L)(X)(X)(V)CDXXXIII Mar 29 05:35 UTC (GMT)
How to convert: write the Hindu-Arabic number 170,201 using Roman numerals: (C)(L)(X)(X)CCI Mar 29 05:35 UTC (GMT)
How to convert: write the Hindu-Arabic number 859 using Roman numerals: DCCCLIX Mar 29 05:35 UTC (GMT)
How to convert: write the Hindu-Arabic number 160,501 using Roman numerals: (C)(L)(X)DI Mar 29 05:35 UTC (GMT)
How to convert: write the Hindu-Arabic number 6,889 using Roman numerals: (V)MDCCCLXXXIX Mar 29 05:35 UTC (GMT)
How to convert: write the Hindu-Arabic number 122,069 using Roman numerals: (C)(X)(X)MMLXIX Mar 29 05:35 UTC (GMT)
How to convert: write the Hindu-Arabic number 90,905 using Roman numerals: (X)(C)CMV Mar 29 05:34 UTC (GMT)
How to convert: write the Hindu-Arabic number 399,642 using Roman numerals: (C)(C)(C)(X)(C)M(X)DCXLII Mar 29 05:34 UTC (GMT)
How to convert: write the Hindu-Arabic number 58 using Roman numerals: LVIII Mar 29 05:34 UTC (GMT)
How to convert: write the Hindu-Arabic number 274,785 using Roman numerals: (C)(C)(L)(X)(X)M(V)DCCLXXXV Mar 29 05:34 UTC (GMT)
How to convert: write the Hindu-Arabic number 13,112 using Roman numerals: (X)MMMCXII Mar 29 05:34 UTC (GMT)
How to convert: write the Hindu-Arabic number 907,986 using Roman numerals: (C)(M)(V)MMCMLXXXVI Mar 29 05:34 UTC (GMT)
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The set of basic symbols of the Roman system of writing numerals

The major set of symbols on which the rest of the Roman numberals were built:

  • I = 1 (one); V = 5 (five);

  • X = 10 (ten); L = 50 (fifty);

  • C = 100 (one hundred);

  • D = 500 (five hundred);

  • M = 1,000 (one thousand);

    • For larger numbers:

    • (*) V = 5,000 or |V| = 5,000 (five thousand); see below why we prefer this notation: (V) = 5,000.

    • (*) X = 10,000 or |X| = 10,000 (ten thousand); see below why we prefer this notation: (X) = 10,000.

    • (*) L = 50,000 or |L| = 50,000 (fifty thousand); see below why we prefer this notation: (L) = 50,000.

    • (*) C = 100,000 or |C| = 100,000 (one hundred thousand); see below why we prefer this notation: (C) = 100,000.

    • (*) D = 500,000 or |D| = 500,000 (five hundred thousand); see below why we prefer this notation: (D) = 500,000.

    • (*) M = 1,000,000 or |M| = 1,000,000 (one million); see below why we prefer this notation: (M) = 1,000,000.

(*) These numbers were written with an overline (a bar above) or between two vertical lines. Instead, we prefer to write these larger numerals between brackets, ie: "(" and ")", because:

  • 1) when compared to the overline - it is easier for the computer users to add brackets around a letter than to add the overline to it and
  • 2) when compared to the vertical lines - it avoids any possible confusion between the vertical line "|" and the Roman numeral "I" (1).

(*) An overline (a bar over the symbol), two vertical lines or two brackets around the symbol indicate "1,000 times". See below...

Logic of the numerals written between brackets, ie: (L) = 50,000; the rule is that the initial numeral, in our case, L, was multiplied by 1,000: L = 50 => (L) = 50 × 1,000 = 50,000. Simple.

(*) At the beginning Romans did not use numbers larger than 3,999; as a result they had no symbols in their system for these larger numbers, they were added on later and for them various different notations were used, not necessarily the ones we've just seen above.

Thus, initially, the largest number that could be written using Roman numerals was:

  • MMMCMXCIX = 3,999.