What this lesson shows
A pond on grid paper with a curvy edge. Follow the edge with short straight pieces and add them: about 18 units. A square inside it has perimeter 12 and a square around it 24, so 18 is reasonable.
The worked example
The lesson works this one step by step: a curvy pond, 18 units around. Then your kid tries one like it on paper.
The steps
- Follow the edge with short pieces
- Count them: about that many units
- Square inside: less. Square around: more
- Polygon: round each side, then add
Helping at home
For a curvy shape, your kid draws short straight pieces along the edge, each about the side of one square, and counts them. Then they draw the biggest square that fits inside and the smallest square around it: the estimate should land between those two perimeters. For a polygon, they round each side to a whole number and add.
If your kid gets stuck
Short pieces, about 1 square long. Then check with two squares.
Watch it with Lux
With Lux, this lesson is a narrated video and a printed page your kid works on. Then Lux helps with the same math on their own worksheet, one question at a time.
More in this unit
- Triangles two ways
- Every name that fits
- Not only the last name
- Solid figures
- Turning does not change it
- Volume by packing cubes
- No gaps, no overlaps
- Volume by formula
- The base is an area
- Find the missing edge
- Two boxes put together
- Nets of solids
- Area of parallelograms and triangles
- The angles of a triangle
- Area of a trapezoid
- Radius and diameter
- Perimeter, area, or volume?
- Surface area with a net