Q: How many different 7 digit phone number are possible if the first digit cannot be 0?

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If you include 0000, ten thousand unique four digit codes are possible.

9,876

Highest 2-digit number = 99 Highest 1-digit number = 9 Highest possible sum from 2, 2-digit numbers = 198 Highest possible sum from 2, 1-digit numbers = 18

It is 891.

There are 4,500 combinations.

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Assuming that the first digit of the 4 digit number cannot be 0, then there are 9 possible digits for the first of the four. Also assuming that each digit does not need to be unique, then the next three digits of the four can have 10 possible for each. That results in 9x10x10x10 = 9000 possible 4 digit numbers. If, however, you can not use the same number twice in completing the 4 digit number, and the first digit cannot be 0, then the result is 9x9x8x7 = 4536 possible 4 digit numbers. If the 4 digit number can start with 0, then there are 10,000 possible 4 digit numbers. If the 4 digit number can start with 0, and you cannot use any number twice, then the result is 10x9x8x7 = 5040 possilbe 4 digit numbers.

If you include 0000, ten thousand unique four digit codes are possible.

9876 (:

hi wazup hi wazup

9,876

9999 is the 4-digit number and 999 is the 3-digit number.

99x9999=989901

A number cannot have a place value - only a specific digit with a number can have a place value.A number cannot have a place value - only a specific digit with a number can have a place value.A number cannot have a place value - only a specific digit with a number can have a place value.A number cannot have a place value - only a specific digit with a number can have a place value.

Highest 2-digit number = 99 Highest 1-digit number = 9 Highest possible sum from 2, 2-digit numbers = 198 Highest possible sum from 2, 1-digit numbers = 18

The number of 3-digit numbers with no repeated digits is simply 10x9x8 = 720, if you allow, for example, 012 as a 3-digit number. There are 10 digits, any of which might be the first digit. The second digit can be any digit except the digit that was used for the first digit, leaving 9 possibilities. The third digit then has 8 possibilities, since it can't be the same as the first or second digit. The actual number of possible area codes will be lower, because there are additional restrictions on the number combinations for a valid area code. For example, in North America (USA, Canada, etc.), the first digit of an area code cannot be 0 or 1 and the middle digit cannot be 9.

It is 891.

A zero