⭕ Primary Maths & Science Games · Grade 6 · Circles
Circle Circumference and Area: Roll It, Count It, Work It Out
The three classic circle slips are using the radius in C = πd, forgetting to square the radius, and writing a ring as 3.14 × (R − r)². Roll the circle once and count squares once, and the formulas make sense. (For cutting a circle into sectors to form a rectangle, see the area cut-and-paste visualizer.)
- Free, no sign-up
- Ad-free play area
- Tablet friendly
- Parent mode
- A4 worksheet
- 5 levels
How to play
- Explore has four views: parts of a circle (drag the orange dot), roll it (one full turn along a line, pause or scrub back), area (count 1 cm squares) and ring (set both radii).
- The readings on the right follow the radius, using π = 3.14.
- Levels: radius and diameter, circumference, working back from the circumference, area, and rings and semicircles. Parents shows the slips and prints worksheets.
Curriculum unit
Primary maths, grade 6: parts of a circle, circumference, area, rings and semicircles (PEP textbook, grade 6 volume 1, unit 5).
For parents and teachers
Mistakes are grouped as radius/diameter swaps, C with the radius and no × 2, doubling the diameter, circumference vs area, forgetting ÷ 2, not squaring, squaring the diameter, ring as (R − r)² and semicircles without the diameter. The worksheet targets the weakest level, with answers.