One- and two-digit numbers
Say the number (6=number six) or (97=ninety-seven).
Three-digit numbers
Say the first digit by itself followed by the two-digit number (923=nine twenty-three).
If there’s a zero in the middle
Say the first digit, then oh, then the last digit (101=one oh one).
Four digits or more
Better to just say each digit (3763=three seven six three) or break it into two-digit numbers (thirty-seven sixty-three).
Use “oh” if the third digit is zero
(3703=three seven oh three) or (thirty-seven oh three).
For more than four digits
Just say each digit (90210=nine oh two one oh).