Allowing leading zeros, 109 or 1 billion.
The number of combinations - not to be confused with the number of permutations - is 2*21 = 42.
9x8x7x6x5x4x3x2x1 or 9! which equals 362880 possible combinations if no digits are repeated
If the numbers can be repeated and the numbers are 0-9 then there are 1000 different combinations.
7878
In a 7 segment display, the symbols can be created using a selected number of segments where each segment is treated as a different element.When 1 segment is used, the possible positions are 7because it can be any of the 7 segments (7C1=7).When 2 segments are used, the number of possible combinations are 7C2=21.When 3 segments are used, the number of possible combinations are 7C3=35When 4 segments are used, the number of possible combinations are 7C4=35When 5 segments are used, the number of possible combinations are 7C5=21When 6 segments are used, the number of possible combinations are 7C6=7When 7 segments are used, the number of possible combinations are 7C7=1Adding the combinations, 7+21+35+21+7+1=127Therefore, 127 symbols can be made using a 7 segment display!
Since a number can have infinitely many digits, there are infinitely many possible combinations.
The number of combinations - not to be confused with the number of permutations - is 2*21 = 42.
9x8x7x6x5x4x3x2x1 or 9! which equals 362880 possible combinations if no digits are repeated
If the numbers can be repeated and the numbers are 0-9 then there are 1000 different combinations.
18 different combinations. When a coin is tossed twice there are four possible outcomes, (H,H), (H,T), (T,H) and (T,T) considering the order in which they appear (first or second). But if we are talking of combinations of the two individual events, then the order in which they come out is not considered. So for this case the number of combinations is three: (H,H), (H,T) and (T,T). For the case of tossing a die once there are six possible events. The number of different combinations when tossing a coin twice and a die once is: 3x6 = 18 different combinations.
7878
In a 7 segment display, the symbols can be created using a selected number of segments where each segment is treated as a different element.When 1 segment is used, the possible positions are 7because it can be any of the 7 segments (7C1=7).When 2 segments are used, the number of possible combinations are 7C2=21.When 3 segments are used, the number of possible combinations are 7C3=35When 4 segments are used, the number of possible combinations are 7C4=35When 5 segments are used, the number of possible combinations are 7C5=21When 6 segments are used, the number of possible combinations are 7C6=7When 7 segments are used, the number of possible combinations are 7C7=1Adding the combinations, 7+21+35+21+7+1=127Therefore, 127 symbols can be made using a 7 segment display!
48
2^n possible combinations
The number of possible combinations of three different words depends on the total number of words available. If you have ( n ) distinct words, the number of combinations of three words can be calculated using the combination formula ( C(n, 3) = \frac{n!}{3!(n-3)!} ). This formula gives you the total ways to choose 3 words from ( n ) without regard to the order of selection. For example, if you have 10 words, the number of combinations would be ( C(10, 3) = 120 ).
35
If repeats are allowed than an infinite number of combinations is possible.