Skip to main content
OlympiadHQ

Browse · harp

Print

jmc

number theory junior

Problem

When Yunji added all the integers from to , she mistakenly left out a number. Her incorrect sum turned out to be a square number. What number did Yunji leave out?
(A)
(B)
(C)
(D)
(E)
Solution
The sum of the integers from to is . Since the nearest square number less than is , the answer is
Final answer
E