When the Chinese count on one hand, they are doing a kind of addition. They can count to much higher than 10 in this way, too, by using their fingers and thumb to denote different units:

• The thumb is used to count 10,000s (10,000, 20,000 and up)
• The index finger is used to count 1,000s (1000, 2000, …)
• The middle finger indicates 100s (100, 200, 300…)
• The ring finger counts – no, not 10s, but 20s (20, 40, 60, 80…)
• The little fingers counts single digits (1, 2, 3, 4, and so on)

It is a very useful way of adding up and you will see it practised often in Chinese markets and shops. If you have trouble remembering the words, try remembering the Chinese way to sign numbers!