Question

How many 2-digit numbers can be formed from the digits 1 through 8 if each digit is only used once?

Answer 1

Answer:

56.

Step-by-step explanation:

That is the number of permutations of 2 from 8

= 8P2

= 8!/(8-2)!

= 8!/6!

= 8 * 7

= 56.

Answer 2

Answer:57

Step-by-step explanation:

12

13

14

15

16

17

18

21

23

24

25

26

27

28

31

32

34

35

36

37

38

41

42

43

45

46

47

48

51

52

53

54

56

57

58

61

62

63

64

65

67

68

71

72

73

74

75

76

78

81

82

83

84

85

86

87

..