Numbers to Words

There are varying opinions amongst writers as to when one should spell out a number vs. using figures. However there are a few generally agreed upon rules for doing so.

There are 2 of them we will follow for this kata:

  • Numbers beginning a sentence should be spelt out.
  • Hyphenate all compound numbers from twenty-one through ninety-nine
Write an implementation of these rules for numbers starting a sentence. It should take an input of figures and return the number spelt out.
Assume all the numbers given start sentences and your code will be used like a spell checker for grammar issues related to numbers.

Only worry about up numbers up to 4 digits long. Assume all numbers are positive.


1 digit 2 digits 3 digits 4 digits
0 = zero 10 = ten 100 = one hundred 2000 = two thousand
5 = five 21 = twenty-one 303 = three hundred three 3466 = three thousand four hundred sixty-six
8 = eight 77 = seventy-seven 555 = five hundred fifty-five 2400 = two thousand four hundred


Solve for 1 digit, then move to 2 digits and so on.


The simplest way to express large numbers is usually best. Instead of 5300 being equal to five thousand three hundred it should return fifty-three hundred. This new rule only applies to 4 digit numbers.


You can find all language solutions here Numbers to Words Solutions
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