First, students will review disproof by counterexample, for algebraic identities devoid of trig functions. Students will review how to disprove such identities by graphing, and how to disprove them by plugging in values that make the equation false. Then students will do the same for trig identities.
Conclude by giving your students these challenges:
- The Number Crunching Machine by NRICH
- Knapsack by NRICH
- Counting Binary Ops by NRICH
Rule: given two consecutive cells on a row, add them together and put the sum in the cell below, as follows:

The following number pyramid is formed by following the stated rule:

Determine the value of \(x.\) Here's the solution.