How many non zero digits are there in the hexadecimal number

How many non zero digits are there in the hexadecimal number How many numbers are there in the phone number 323-5568? How many [ ] are there in the hospital? How many countries are there in the How many letters are there in the worid?There are( ). ----how many staff are there in the office? ----there are___ how many flavours are there in the square? how many triangles are there in the shape below? how many boys are there in the picture? How many states are there in the United States ? How many continents are there in the world?翻译 how many doors are there in the Paris Opera House