The number of seven-digit phone numbers that can be formed that begin with 353 with not all of the last four digits 0 is 94 .

Question

Quizplus · Accepted Answer

The number of seven-digit phone numbers that can be formed starting with 353 and not having all of the last four digits as 0 is 9,999. This is because each of the last four positions can have any digit from 0 to 9 (10 possibilities each), making it $10^4 = 10,000$ total combinations. However, we must exclude the case where all four digits are 0, leaving us with $10,000 - 1 = 9,999$ valid phone numbers.

The Number of Seven-Digit Phone Numbers That Can Be Formed