Counting before numbers
数字（发明）前的计数
Before the invention of written numbers, people used many different ways to count things.
在数字发明之前，人们采用不同的方式来对东西计数。
At first, people used their fingers, and even their toes.
一开始，人们用他们的手指，连同自己的脚趾。
However, they could only count small numbers in this way.
然而，他们也只能指望这样来计算小的数字。
After that, they began to make small marks on sticks and bones.
后来，他们开始用棍棒和骨头制作一些小物件。
This helped them count bigger numbers.
这有助于依靠它们计算更大的数字。
They used them to count things like the days of the month, the amount of food and the number of animals they had.
他们依此来计算如每个月天数、他们拥有的食物和动物数量（那样的数字）。
Then people began to use tokens made from clay or small stones.
再后来人们开始使用由粘土或小石块做成小物件。
This helped them count even bigger numbers.
这可以用来计算更大的数字。
They often put the tokens on pieces of string so that they could carry them around easily.
他们通常会它们穿成串儿，以方便他们携带。
This developed into tools like the abacus.
这就发展成了如算盘的工具。
Finally, people began to develop systems of written marks to show different numbers,
最后，人们开始扩展文字系统，用来显示不同的数字，
and this led to the Hindu-Arabic system (0-9).
于是产生了印度 - 阿拉伯数字（0-9）。
We are still using this system today.
直到今天，我们仍然在使用这套（数字）系统。
