Lê Quốc Trần Anh Coordinator
22/07/2018 at 03:27-
We have: 5 = 1 + 0 + 4 = 1 + 1 + 3 = 1 + 2 + 2 = 2 + 0 + 3 = 5 + 0 + 0
With 1, 0, 4, we can have 4 three-digit numbers including these 3 numbers
(104, 140, 401, 410)
With 1, 1, 3, we can have 3 three-digit numbers including these 3 numbers
(113, 131, 311)
With 1, 2, 2, we can have 3 three-digit numbers including these 3 numbers
(122, 212, 221)
With 2, 0, 3, we can have 4 three-digit numbers including these 3 numbers
(203, 230, 302, 320)
With 5, 0, 0, we can have 1 three-digit number including these 3 numbers
(500)
In total, we have 4 + 3 + 3 + 4 + 1 = 15 (numbers)
Lê Quốc Trần Anh selected this answer. -
Lê Anh Duy 22/07/2018 at 14:28
We have: 5 = 1 + 0 + 4 = 1 + 1 + 3 = 1 + 2 + 2 = 2 + 0 + 3 = 5 + 0 + 0
With 1, 0, 4, we can have 4 three-digit numbers including these 3 numbers
With 1, 1, 3, we can have 6 three-digit numbers including these 3 numbers
With 1, 2, 2, we can have 6 three-digit numbers including these 3 numbers
With 2, 0, 3, we can have 4 three-digit numbers including these 3 numbers
With 5, 0, 0, we can have 1 three-digit number including these 3 numbers
In total, we have 4 + 6 + 6 + 4 + 1 = 21 (numbers)