What is on a handout

  • The big idea: the rule, in a few short sentences.
  • Watch me: worked examples, each with why it changes as it does.
  • Watch out: the mistakes children often make, struck through beside the right answer.
  • Try it together: a few items or problems to do as a class, with an answer key.
  • On your own: the practice sheet that comes next.

How to teach with it

  • Test a law by putting a negative number and a fraction in for the letters. If it fails once, as 7 − 2 and 2 − 7 do, it is not a law. At Grade 8, name the property behind each step of simplifying or solving: doing the same to both sides keeps an equation true, and dividing an inequality by a negative number turns its sign around.
  • Read the big idea aloud, then work through Watch me together, saying why each one changes.
  • Ask the class to find the mistake in each Watch out before you show the answer.
  • Do Try it together as a class, check it with the answer key, then hand out the practice sheet.

Practice worksheets

After the handout, in this order: the main practice sheet first, then more practice, then quick checks.