Students will learn how to find the formula for an arithmetic sequence given two of its terms. Using the two terms, we can setup a system of two equations in two unknowns. Solving gives us the common difference. Then plugging in the common difference, and one of the known terms, we can find the value of the first term.
Next, give your students these challenges:
Conclude by leading this investigation:
Pinocchio’s Playmates (pattern puzzle)