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Ecuador Mathematical Olympiad (OMEC)
2023 Ecuador NMO (OMEC)
4
4
Part of
2023 Ecuador NMO (OMEC)
Problems
(1)
Counting problem with digits
Source: OMEC Ecuador National Olympiad Final Round 2023 N3 P4 day 2
11/6/2024
A number is additive if it has three digits, all of them are different and the sum of two of the digits is equal to the remaining one. (For example,
123
(
1
+
2
=
3
)
,
945
(
4
+
5
=
9
)
123 (1+2=3), 945 (4+5=9)
123
(
1
+
2
=
3
)
,
945
(
4
+
5
=
9
)
). Find the sum of all additive numbers.
national olympiad
combinatorics