Như Nguyễn Thị Quỳnh
24/05/2017 at 14:25-
Trần Nhật Quỳnh 24/05/2017 at 14:28The number of 4-digit numbers is: (9999 - 1000): 1 + 1 = 9000 (number)
If you do not use numbers 2 and 3, then you have eight digits left to form units, tens and hundreds. Since zeros can not be used to make thousands of digits, there are only seven digits left to make thousands. According to the kernel rule, we have: 8 x 8 x 8 x 7 = 3584 (number)
Inference: A 4-digit number containing two digits, or three or both, is 9000 - 3584 = 5416 (number).
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→இے๖ۣۜBoy™†hïếuGîa 02/06/2017 at 10:10The number of 4-digit numbers is: (9999 - 1000): 1 + 1 = 9000 (number)
If you do not use numbers 2 and 3, then you have eight digits left to form units, tens and hundreds. Since zeros can not be used to make thousands of digits, there are only seven digits left to make thousands. According to the kernel rule, we have: 8 x 8 x 8 x 7 = 3584 (number)
Inference: A 4-digit number containing two digits, or three or both, is 9000 - 3584 = 5416 (number). -
Lê Mạnh Tiến Đạt 31/05/2017 at 17:03The number of 4-digit numbers is: (9999 - 1000): 1 + 1 = 9000 (number)
If you do not use numbers 2 and 3, then you have eight digits left to form units, tens and hundreds. Since zeros can not be used to make thousands of digits, there are only seven digits left to make thousands. According to the kernel rule, we have: 8 x 8 x 8 x 7 = 3584 (number)
Inference: A 4-digit number containing two digits, or three or both, is 9000 - 3584 = 5416 (number). -
Lê Mạnh Tiến Đạt 31/05/2017 at 17:02
The number of 4-digit numbers is: (9999 - 1000): 1 + 1 = 9000 (number)
If you do not use numbers 2 and 3, then you have eight digits left to form units, tens and hundreds. Since zeros can not be used to make thousands of digits, there are only seven digits left to make thousands. According to the kernel rule, we have: 8 x 8 x 8 x 7 = 3584 (number)
Inference: A 4-digit number containing two digits, or three or both, is 9000 - 3584 = 5416 (number).