Today is rung 7 of 7 on this topic
Area and perimeter
Can do: Finds the area of a rectangle by multiplying, and the perimeter by adding โ and knows which is which.
Why it matters
Area is where multiplication becomes geometric, and the two ideas are permanently confused unless they're built physically.
What it looks like when it's wobbly
Swaps the two, adds when they should multiply, and forgets the units are different โ cm versus cmยฒ.
โฑ๏ธ Two-minute check
Draw a 4 by 6 rectangle. "What's the area? What's the perimeter?"
Solid looks like: 24 square units and 20 units, with the right units named.
The full activity for this topic ยท 15 minutes
Tile It and Fence It
- 1Cover a rectangle with square tiles and count them โ that's area, and it's a multiplication.
- 2Walk a finger round the edge and count the units โ that's perimeter, and it's a fence.
- 3Use the words every time: fence for perimeter, floor for area.
- 4Measure a real room or a table and calculate both.
- 5Show two shapes with the same perimeter and different areas. It surprises them, and it should.
If it's too hard
Count the squares rather than multiplying.
If it's too easy
Find a missing side given the area, or the area of an L-shape split into two rectangles.
Say this
"Fence or floor? The fence goes round the edge. The floor is what you cover with tiles."
