what is the least possible sum of two 4-digit numbers?what is the least possible sum of two 4-digit numbers?
The first digit can have 5 possible numbers, the second digit can have 4, the third 3, the fourth 2. 5
Add the two greatest possible four digit numbers. 9999 + 9999
There are 4 possible numbers if the digits are not repeated; 18 if they are. Those are 3-digit numbers, assuming that zero would not be a leading digit. If zero is allowed for a leading digit, then you can have 6 for the non repeated, and 27 if repetition.
There are 210 4 digit combinations and 5040 different 4 digit codes.
what is the least possible sum of two 4-digit numbers?what is the least possible sum of two 4-digit numbers?
There are 2941 4-digit numbers such no two of its digits differ by 1.
The first digit can have 5 possible numbers, the second digit can have 4, the third 3, the fourth 2. 5
Without repeats there are 4 × 3 = 12 possible 2 digit numbers. With repeats there are 4 × 4 = 16 possible 2 digit numbers.
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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.
Add the two greatest possible four digit numbers. 9999 + 9999
There are 4 possible numbers if the digits are not repeated; 18 if they are. Those are 3-digit numbers, assuming that zero would not be a leading digit. If zero is allowed for a leading digit, then you can have 6 for the non repeated, and 27 if repetition.
If two digit number can have a repeated digit (eg 44) then there are 20 possible numbers, otherwise there are 16 possible numbers: There are 4 single digit numbers; With repeats allowed there are a further 4 x 4 = 16 two digit numbers making a total of 20; Without repeats allowed there are a further 4 x 3 = 12 two digit numbers making a total of 16.
There are many possible answers to this question ... for example, 9000, 2000, and 111. Can you be more specific?
It can have 4 digits, because the highest possible two digit numbers 99*99=9801.