MYSTERY SUMS, PART ONE—DEDUCE THE UNKNOWN ADDENDS

Students use logical and early algebra reasoning skills to deduce the numerical values of four variables, A, B, C, and D. Students receive clues to these values by dragging pairs of variables across a divider to reveal their sum. By using guess and check or informal algebraic reasoning, students deduce the value of each letter. Students play the game multiple times and create and share their own challenges with each other.

OBJECTIVES
• Students will develop a systematic approach for listing and sorting through possible solutions to an algebraic equation.
• Students will use logical reasoning skills to determine the secret numerical values assigned to variables.
• Students will develop, refine, and share intuitive strategies for solving algebraic equations without formal symbol manipulation.

COMMON CORE CONNECTIONS
Mathematical Practices

(1) Make sense of problems and persevere in solving them; (2) Reason abstractly and quantitatively; (3) Construct viable arguments and critique the reasoning of others; (5) Use appropriate tools strategically; (7) Look for and make use of structure.

Content Standards

6.EE2, 5, 6; 7.EE4; 8.EE8 