In the 13th century, Cistercian monks worked out a system of numerals in which a single glyph can represent any integer from 1 to 9,999:

Once you’ve mastered the digits in the top row, you can represent tens by flipping them (second row), hundreds by inverting them (third row), and thousands by doing both (fourth row). And now you can combine these symbols to produce any number under 10,000:

The monks eventually dropped the system in favor of Arabic numerals, which reached northwestern Europe at about the same time, but it was being used informally elsewhere as recently as the early 20th century.