Roman numerals 1 to 20

Past ten: how the teens are built

One to twenty carries you through the first full cycle of the tens. Eleven to nineteen are just X followed by the one-to-nine numerals you already know: XI, XII, XIII, then XIV with its subtractive four, up through XIX with its subtractive nine. Twenty is XX, two tens side by side. There is no new symbol to learn here, only the pattern of a ten on the left with a unit built on the right.

XII is worth singling out, because it is the number at the top of a clock face and the count of months, hours and zodiac signs. XVIII shows up as a milestone-birthday numeral, and XXI, just past this range, is the coming-of-age one. Seeing the teens laid out in a column makes the repeating shape obvious in a way a single lookup never does.

The subtractive pairs to watch

Two values in the teens use subtraction: XIV (fourteen) and XIX (nineteen). Both follow the same rule as IV and IX in the first ten, so once you have those, the teens hold no surprises. Everything else in this range is purely additive, read straight across from the largest symbol to the smallest.

A common mistake is to write fourteen as XIIII or nineteen as XVIIII by stacking strokes. The chart shows the correct forms plainly, which is exactly why a printed reference beats guessing: you can check the shape against the row before you commit it to ink or paper.

A handy classroom range

One to twenty is a favourite teaching range because it is long enough to show the repeating pattern of tens and units, but short enough to fit on a single card. It covers the numbers most children need first: dates up to the twentieth, list items, and the hours of a clock. Use the live converter above to quiz yourself, then print the chart for the wall.