123456789
With no digit rejected, 999999999 With no digit repeated, 987654321
987654321 is the highest nine-digit number with no repeated digits.
If repeated digits are allowed, then the largest 12-digit number is 999,999,999,999 .If repeated digits are not allowed, then the largest 12-digit number is 989,898,989,898 .If the same digit can't be used more than once, then the largest possible number has only10 digits. The number is 9,876,543,210 .
5 digit telephone numbers having at least one of their digits repeated is = total possible 5 digit telephone numbers - 5 digit telephone numbers without any digit being repeated. =(10*10*10*10*10)-(10*9*8*7*6) =100000-30240 =69760
9x8x7x6x5x4x3x2x1 or 9! which equals 362880 possible combinations if no digits are repeated
What is the least possible 6 digit odd number with only using 1 to 9 once
With no digit rejected, 999999999 With no digit repeated, 987654321
987654321 is the highest nine-digit number with no repeated digits.
102345678 If you allow decimals: 0.12345678 If you allow negative numbers: -987654321
172803456069120
The least three-digit number that is divisible by both 5 and 9 is 135.
If repeated digits are allowed, then the largest 12-digit number is 999,999,999,999 .If repeated digits are not allowed, then the largest 12-digit number is 989,898,989,898 .If the same digit can't be used more than once, then the largest possible number has only10 digits. The number is 9,876,543,210 .
5 digit telephone numbers having at least one of their digits repeated is = total possible 5 digit telephone numbers - 5 digit telephone numbers without any digit being repeated. =(10*10*10*10*10)-(10*9*8*7*6) =100000-30240 =69760
9x8x7x6x5x4x3x2x1 or 9! which equals 362880 possible combinations if no digits are repeated
123,456,789
111 111 111 If you multiply 12345679 by any two digit number* where the first digit is less than 9 and the sum of the digits is 9 (eg 36), the answer will consist of a single digit repeated 9 times. This will be the first digit of the two digit number plus 1 (eg multiplying by 36 will create an number consisting of only the digit 3+1 = 4: 12345679 x 36 = 444 444 444). *Multiplying by 9 is multiplying by the "two" digit number "09", giving an answer consisting of the single digit 0+1 = 1 repeated.
If the same digit can be repeated in the 4-digit number, then there are (9 x 10 x 10 x 10) = 9,000 of them.If the same digit can't be repeated in a 4-digit number, then there are (9 x 9 x 8 x 7) = 4,536 of them.