Difference between revisions of "1992 OIM Problems/Problem 1"

Revision as of 13:53, 13 December 2023

For each positive integer $n$ , let $a_n$ be the last digit of the number. $1+2+3+\cdots +n$ . Calculate $a_1 + a_2 + a_3 + \cdots + a_{1992}$ .

~translated into English by Tomas Diaz. ~orders@tomasdiaz.com

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 == Problem ==
-For each positive integer 4n<math>, let </math>a_n<math> be the last digit of the number. </math>1+2+3+\cdots +n<math>. Calculate </math>a_1 + a_2 + a_3 + \cdots + a_{1992}$.
+For each positive integer <math>n</math>, let <math>a_n</math> be the last digit of the number. <math>1+2+3+\cdots +n</math>. Calculate <math>a_1 + a_2 + a_3 + \cdots + a_{1992}</math>.
 ~translated into English by Tomas Diaz. ~orders@tomasdiaz.com