How to count in Persian
Persian numbers are regular and quick to learn once you have one to ten and the tens.
One to ten: yek, do, se, chahar, panj, shesh, haft, hasht, noh, dah یک، دو، سه، چهار، پنج، شش، هفت، هشت، نه، ده. These ten are the foundation for everything else.
Eleven to twenty
The teens are mostly their own words: yazdah (11), davazdah (12), sizdah (13), chahardah (14), panzdah (15), shanzdah (16), hefdah (17), hejdah (18), noozdah (19), bist (20).
The tens and beyond
Bist (20), si (30), chehel (40), panjah (50), shast (60), haftad (70), hashtad (80), navad (90), sad (100). For in-between numbers, join with o (and): bist o yek is 21, chehel o panj is 45.
The Persian digits
Iran writes numbers with its own digit shapes: ۰ ۱ ۲ ۳ ۴ ۵ ۶ ۷ ۸ ۹ for 0 to 9. You will see these on prices, phone numbers, and signs, so it helps to recognise them.
Learn one to ten and the tens, use o to bridge, and you can say any number up to a hundred without memorising every one.