Opening a ten · Ages 7–8
32 − 5: what if there are only 2 ones?
Does your child say “you can’t do 2 minus 5, so I do 5 minus 2” and get 33 for 32 − 5? It isn’t necessarily carelessness: they forget that 32 is also 3 tens, which hold objects. This free printable shows how to open a ten, with questions instead of corrections, envelopes of ten counters and grids to draw on.
Download the printable (PDF, 2 pages)US Letter size. Print single-sided, at 100% (actual size). Black and white is fine.
Page 1, for you
- Why “5 minus 2” is a logical idea, and what the clue “you end up with fewer than you started with” does and doesn’t catch.
- The key idea, in a simple diagram: open an envelope without changing the total (3 envelopes and 2 loose become 2 envelopes and 12 loose; still 32).
- Three things to watch: opening doesn’t change the total, you only need to open one if the loose counters aren’t enough, and there are other ways to take away.
- Four questions to ask instead of correcting.
- The activities: four small paper envelopes and forty-five small identical objects, out of reach of toddlers; give your child only page 2.
- Notes to read after your child has worked it out, and a cut-out slip for a few days later.
Page 2, for your child
- A page with written instructions, which your child fills in.
- Rafa says “You can’t do 2 minus 5… so 5 minus 2: 33 will be left!”: “Do you agree with Rafa?”
- Six steps: predict, open an envelope, check, decide whether to open (34 − 3, 30 − 4, 41 − 3, 25 − 8), explain, then a family challenge.
- Two grids, “Before” and “After,” with bars of ten and squares to draw when there are no counters at hand.
Our videos for parents
This printable goes with the “Opening a ten” episode of “Understand the concept,” our video series for parents. Find our videos on Ludip’s YouTube channel.
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