Preview · the opening missionRead this to the class:
A Grade 3 class wanted a new rug for their reading corner. Maya measured the corner and said, "It's 12 feet long." Jayden measured it and said, "No, it's 15 feet long." They both used their own feet, heel to toe, and they both counted carefully. The store said, "We can't sell you a rug until you tell us one number we can trust." Your team's job: find out why careful counters got different answers, and find a way to measure that everyone will agree on.
Teams of three, with jobs that rotate: Walker (steps or lays the stick), Counter (counts out loud and checks for gaps), Recorder (writes every number).
Look inside the PDF
Sample pages, stamped “preview”. The download is the clean, full lesson.
In the full lesson PDF
- Predict (5–10 min)
- Hunt (20 min)
- Reveal (10–15 min)
- Act (10 min)
- Background for the teacher
- Assessment
- Student sheet
On the student sheet
- My prediction
- Our measurements of the taped line
- My foot
- What did we find?
- My note about the rug
- Exit ticket
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 / C$25 for all 4 lessons in this unit.
What students show by the end
- Measures with a standard tool
- Explains unit size
- Uses data in a claim
From the lesson’s rubric, which scores each one as not yet, getting there or got it.
Questions teachers ask
How long does “Whose foot is the right ruler?” take?
50–60 min. Group size: teams of 3.
How much prep does it need?
15 minutes: tape a straight start line and finish line on the floor about 5 m (16 ft) apart, in a hallway or across an open part of the room. Measure it yourself so you know the true length. Check that each ruler's 0 is at the very end, or note where 0 is. Draw a blank line plot from 15 to 25 cm in half-centimetre steps on chart paper.
What materials do I need?
Masking tape or painter's tape; metre stick (or a 3 m measuring tape); 30 cm (12 in) ruler; scrap paper and a pencil for tracing feet; chart paper and sticky dots or a marker for the class line plot. Cost: free if you have metre sticks; about $20 for 6 metre sticks and a roll of masking tape.
Which curriculum standards does it cover?
Common Core Math (US): 3.MD.B.4 and 2.MD.A.2.
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 measurements of the taped line”, “My foot”, “What did we find?”, “My note about the rug” and “Exit ticket”) 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 (C$25) for all 4 lessons, yours to keep, or every lesson is US$79 (C$109) a year.