Florida B.E.S.T. MA.2.GR.2.1
The Standard
Explore perimeter as an attribute of a figure by placing unit segments along the boundary without gaps or overlaps. Find perimeters of rectangles by counting unit segments.
Florida B.E.S.T. Standards for Mathematics
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students place equal-length units end to end along the outside edge of a polygon. They count the units around a rectangle to find its perimeter.
What Mastery Looks Like
- A student can mark equal unit lengths along every side and find the total without skipping or repeating sections. They state the perimeter with a length unit and explain that it measures the outside boundary.
Common Misconceptions
- Students may count the squares inside a figure instead of the unit lengths around it. They may leave gaps, overlap units, skip a side, or count corner points as units.
How to Assess It
- Give students a 3-by-5 rectangle on a unit grid. Ask them to mark each boundary segment and write the perimeter with its unit.
Lesson moves
Ways to Teach It
Build rectangles with one-inch craft sticks placed end to end, then count the sticks around each boundary.
Ask students to explain why counting the inside squares does not give the perimeter.
Play a card sort matching grid rectangles to perimeter totals, with students checking each match by tracing and counting boundary units.
Measure the edge of a book cover with equal-size paper clips, making sure the clips do not overlap or leave gaps.
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Printable MA.2.GR.2.1 Worksheet
A ready-to-print activity worksheet aligned to MA.2.GR.2.1, with an answer key for the teacher on its own page. No account needed.
PDF, US Letter, prints cleanly in black and white.
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