16 times
998,000
The question is incorrect since there are 210 - 1 possible combinations. The digit 0 can be in the combination or out. That gives 2 ways. With each, the digit 1 can be in the combination or out - 2*2 = 22 ways. With each, the digit 2 can be in the combination or out = 23 ways. With each, the digit 3 can be in the combination or out = 24 ways. etc. So 210 ways in all except that one of them is the null combination. Now 210 = 1024 so there are only 1023 combinations. If, instead, you allow the digits to be used many times, there is no limit to the number of combinations.
Only 1. In a combination, the order of the numbers does not matter. So 102478 is the same combination as 104782 or 407812 etc.
That depends a lot on how often you may repeat each digit, and what operations are allowed. If you just want to write a four-digit number, using each digit once, start by writing the largest digit on the left, then continue with the second-largest, etc.
97531
the place of each digit help the value of the number by using your multuplication
There can be only 1 combination since, in a combination, the order of the digits does not matter. So, since you must have each digit once and only once, the only combination is 3456.
61
The question is incorrect since there are 210 - 1 possible combinations. The digit 0 can be in the combination or out. That gives 2 ways. With each, the digit 1 can be in the combination or out - 2*2 = 22 ways. With each, the digit 2 can be in the combination or out = 23 ways. With each, the digit 3 can be in the combination or out = 24 ways. etc. So 210 ways in all except that one of them is the null combination. Now 210 = 1024 so there are only 1023 combinations. If, instead, you allow the digits to be used many times, there is no limit to the number of combinations.
998,000
Only 1. In a combination, the order of the numbers does not matter. So 102478 is the same combination as 104782 or 407812 etc.
943
That depends a lot on how often you may repeat each digit, and what operations are allowed. If you just want to write a four-digit number, using each digit once, start by writing the largest digit on the left, then continue with the second-largest, etc.
It is: 401
97531
Proceed from left to right, using the largest possible digit in each position.
You have a three digit number that can only use each digit once in combination. Therefore, a number like 456 is acceptable, but 455 or 101 or 222 is not acceptable. I think you can solve the problem in the following manner. There are 10 possible digits (0-9) that can be used in the first number. For the second number there are only 9 possible since you cannot repeat one of the first. For the third number there are only 8 possible since again you cannot repeat any of the first two. You multiply the possibilities for each digit to get our answer. 10 * 9 * 8 = 720 There are 720 possible combinations.