Preview · the opening missionRead this to the class:
The class is making a new reading rug from 24 square carpet tiles. Every tile edge on the outside of the rug needs a strip of edging tape sewn on, and the tape costs one dollar for each tile edge it covers. "It's the same 24 tiles whatever we do," said the principal, "so the edging will cost the same." Your team's job: build every rectangle rug you can from the 24 tiles, and find out whether the edging really costs the same.
Teams of three, with jobs that rotate after each rug: Builder (lays the tiles), Edge Counter (counts the tile edges around the outside), Recorder (writes the length, width, area and perimeter).
Look inside the PDF
Sample pages, stamped “preview”. The download is the clean, full lesson.
In the full lesson PDF
7 printable pages
- Predict (5–10 min)
- Hunt (20 min)
- Reveal (10–15 min)
- Act (10 min)
- Background for the teacher
- Assessment
- Student sheet
- Worksheet: Label it
- Worksheet: Try it at home
On the student sheet
- My prediction
- Our rugs
- What did we find?
- Draw it
- My note to the principal
- Exit ticket
- Label it
- Try it at home
US Letter, prints cleanly in black and white. The student sheet is on its own page, ready to photocopy.
Free with an account (any 3 lessons), or US$19 for all 4 lessons in this unit.
What students show by the end
- Builds rectangles of a given area
- Finds perimeter
- Finds a missing side
From the lesson’s rubric, which scores each one as not yet, getting there or got it.
Questions teachers ask
How long does “Can the same rug need more edging?” take?
45–60 min. Group size: teams of 3.
How much prep does it need?
15 minutes: give each team 24 identical squares. Use square plastic tiles, or cut 5 cm (2 in) squares from card stock or old file folders (24 per team, so 240 for 10 teams; a paper cutter makes this quick). Each team also needs a sheet of grid paper and a pencil.
What materials do I need?
Square tiles or 5 cm (2 in) card squares, all the same size; grid paper; coloured pencils. Cost: free with paper squares; about $15 for a class set of square tiles.
Which curriculum standards does it cover?
Common Core Math (US): 3.MD.C.7 (partly), 3.MD.D.8 and 4.MD.A.3.
What’s in the lesson PDF?
A teacher guide that walks you through predict, hunt, reveal, act, background for the teacher and assessment, then a student sheet (“My prediction”, “Our rugs”, “What did we find?”, “Draw it”, “My note to the principal”, “Exit ticket”, “Label it” and “Try it at home”) on its own page, ready to photocopy. It’s US Letter and prints cleanly in black and white.
Can I try it for free?
Yes. A free account includes any 3 full lessons of your choice, and this can be one of them. After that, this unit is US$19 for all 4 lessons, yours to keep, or every lesson is US$199 a year.