The problem of the week will return in the Fall 21 semester. We thank everyone who participated this Spring. In particular, we would like to recognize two participants who contributed most solutions during the last 3 semesters: Yuqiao Huang and Ashton Keith. Each of them will receive a $250 prize from DOMS.

For the Summer, we suggest reviewing problems from past semesters and working on the additional problems posted at the bottom of the provided solutions.

• Problem 7 Solved by Ashton Keith and John Mignone.

• Problem 6 No solutions were submitted.

• Problem 5 Solutions received from John Mignone and Yuqiao Huang.

• Problem 4 Solutions received from Paul Barber and Ashton Keith.

• Problem 3 Solved by Paul Barber, Yuqiao Huang, Prof. Vladislav Kargin, and Ashton Keith.

• Problem 2 Only one solution was submitted, by Ashton Keith.

• Problem 1 Solved by Chris Eppolito, Yuqiao Huang, Ashton Keith, Maxwell T Meyers, and Wei Yang.