How many three digit number can be made using the digit 0,1,2,3,4,5,6,7,8,9 if no digit is repeated
Answers
Answer:Nine
Step-by-step explanation:There are nine possible first digits, because numbers beginning in 0 drop the 0, so 012 is really just 12, a two digit number. The first digit must be 1 thru 9, nine possible digits.
The second digit can be any of the nine digits left after you take the first digit out of the pool of choices. So 9*9 ways to chose the first two digits.
The third digit can be any of the 8 digits left after you take the first two digits out of the pool. So 9*9*8=648 total three digit numbers, from 102 to 987
Except that you didn’t really define what a “number” is here. So, is 1.23 a three digit number?
If 12.3 is a three digit number, then there are again 9 possible first digits, 9 possible second digits, but only 9–2 third digits, because 0 cannot be the third digit now; just as in 012, 12.0 is really just 12, you drop the trailing zero after a decimal. So 9*9*7=567 three digit numbers with one past the decimal place
Then there are the numbers like 1.23. Here, we get to count 0.12 as a three digit number, a leading zero before the decimal is retained. So there are 10 possible first digits, 9 possible second digits, and… 9–2 possible third digits because again, no trailing 0. 1.20 is really just 1.2. That makes 10*9*7=630 numbers.
Summing up, 648+567+630=1845 positive numbers you can make with those digits and no repetition.
Positive numbers? You didn’t actually specify that. SO there are exactly the same number of negative numbers, each the same as it’s positive counterpart, only with a - in front.
New total: 1845*2=3690
SO you can see it’s imperative that you tell us what a “number” is, if you want a clear answer to a question like this one.
Answer:
Answer = 9
Step-by-step explanation:
Hope It helps you