When you divide 10 by 3, the result is 3.33333…, a number with digits that repeat infinitely. Such numbers are called repeating decimals (or periodic numbers).
In mathematics, repeating digits are often shown using either a dot or a bar above the repeating part, you can easily create both of these notations with PopChar using Unicode combining characters. The technique used is similar to the one described in “Writing letters with a bar on top”.
Understanding combining characters
Unicode includes a special set of characters called Combining Diacritical Marks.
These characters have zero width — meaning they don’t take up space on their own — but instead overlay the character before them.
This makes them perfect for adding dots, bars, or other marks above digits or letters.
Adding a dot or a bar above a digit
To create a repeating decimal using the dot notation (for example, 3̇), follow these steps:
- Type the base character (for example, 3).
- In PopChar, search for “combining dot above” or type “combi dot” in the search field.
- Click the COMBINING DOT ABOVE character to insert it.
If you want to use the bar notation instead, you can use the COMBINING MACRON character to insert it.
Extending the bar over multiple digits
If you want a bar over two or more digits, you can use the COMBINING DOUBLE MACRON character. This character extends over both the preceding and following character, which avoids a visible gap between bars.
To create this effect:
- Type your digits (for example, 81).
- Use PopChar to insert COMBINING DOUBLE MACRON.
- Insert it in all positions after the first and before the last digit.
Note: The appearance of combining marks can vary between fonts.
Try experimenting with different fonts like Helvetica, Times, or Arial to find one that looks best.
(*) The last version of 0.81 in these lines was made with a double macron between 8 and 1.