Counting on to and back from 20. When you count to 20, you start at 1 (or zero) and count on until you reach 20. Each number is one more than the last.

Bluesky saw its user count hit and surpass 20 million on Tuesday, ... Now that number has dropped to just 1.5. Bluesky has also since surpassed Threads in website visits in both the US and the UK.

Tzotzil, base-20 body part counting. ... Supyire, a Niger-Congo language spoken in Mali has basic number words for 1, 5, 10, 20, 80 and 400, and builds the rest of the numbers from those.