Ninth graders learn to recognize and extend arithmetic sequences (adding a common difference) and geometric sequences (multiplying by a common ratio), and to use formulas to find any term.
Students will be able to…
2, 5, 8, 11… versus 2, 6, 18, 54… — both are patterns, but they grow very differently. What’s the rule behind each, and how do you find the 100th term?
Project this and tap each idea. Have students learn the difference between adding (arithmetic) and multiplying (geometric) sequences!
Tap any phase to open the teacher moves and student actions.
2,5,8,11 vs. 2,6,18,54 — how do these patterns differ?
Teacher models.
Class uses the Sequence Explorer.
Students work sequences.
One sequence.
Aligned to the Common Core State Standards for Mathematics (High School Algebra).
Write arithmetic and geometric sequences recursively and explicitly.
Construct linear and exponential functions from a sequence.
Recognize that sequences are functions.
Write a function that describes a relationship.
Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.
Have students use the explicit formula aₙ = a₁ + (n−1)d to find a far-out term without listing them all. A printable sequences sheet is in the Math library.
Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.
A quick self-check with instant feedback, drawn from this lesson’s key terms.
A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.