Undoing the steps (i.e. backtracking) provides a lot of good intuitions for students, and the technique connects to work in expressions and finding inverse functions.

Guess-Check-Generalize is powerful, and I see it being exercised with a good 3 Act problem. Maybe this one.

Here’s an idea for an activity that turns the equation-solving process backwards.

Still looking for:

Some good 3 Acts problems

A sense of how to deliberately connect this topic to probability, statistics, previous stuff, quadratic equations and absolute value equations.

I need some help with literal equations. Kids have a lot of trouble with them – how can I help?