Depth 1 · 34 s
Ten signs
Twenty-three sheep as tally marks, as Roman numerals, and as just two signs. The ten numerals invented in India can write any number, however big, in a few signs.
About this video
Numerals are the signs we write numbers with, and people have tried several ways of doing it. This short animation writes twenty-three sheep three ways. Tally marks are the oldest: one mark for each sheep, tied into bundles of five so they are easier to count. Roman numerals were cleverer, with signs for groups: X for ten, V for five and I for one, so twenty-three is XXIII, signs added up.
Today we write it with two signs, 2 and 3, because the place of a digit says what it is worth: the 2 means two tens. The difference shows with a bigger number. For 1,388, tally marks fill a wall, the Roman numeral is MCCCLXXXVIII, twelve signs long, and our numerals need only four. Those ten signs, 0 to 9, were invented in India, and they reached Europe through the Persian and Arab world, which is why they are often called Hindu-Arabic numerals. With just ten signs you can write any number at all. This video goes with the From Tally Marks to Numerals lesson of Numbers Level 1 on Knaph.
This video shows depth 1 of Numerals.
Learn NumeralsTranscript
- 0:00How would you write down twenty-three sheep?
- 0:04With tally marks, one mark for every sheep, in bundles of five.
- 0:09The Romans used signs for groups. X is ten, I is one.
- 0:14Today we need two signs. A two for two tens, and a three.
- 0:19For thirteen eighty-eight, tallies fill a wall. Four signs are enough.
- 0:25Ten signs, from India, through the Persian and Arab world.
- 0:29Ten signs write any number.