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

  • Draw an open number line with the start time, the hour, and the end time, and write the minutes on each jump. Seeing the jump to the hour stops students subtracting the times as if they were whole numbers.
  • 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.