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2015 Online Math Open Problems
1
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Part of
2015 Online Math Open Problems
Problems
(2)
2014-2015 Spring OMO #1
Source:
4/14/2015
What is the largest positive integer which is equal to the sum of its digits?Proposed by Evan Chen
Online Math Open
2015-2016 Fall OMO #1
Source:
11/18/2015
Evaluate
(
8
2
)
+
(
9
2
)
+
(
15
2
)
+
(
16
2
)
.
\sqrt{\binom82+\binom92+\binom{15}2+\binom{16}2}.
(
2
8
)
+
(
2
9
)
+
(
2
15
)
+
(
2
16
)
.
Proposed by Evan Chen
Online Math Open