Perimeter and area · Usually met around P4
What area is
Cover with one unit and count.
How to do it
Method
Cover with one unit and count
A takes 12 squares, B takes 10: A is bigger
Another way
Lay one on the other
A covers B with some left over: A is bigger
In full
Area is how much flat space a surface or shape covers. To compare two areas, lay one on the other: the one that covers the other with some left over is bigger. If they can't be laid together, cover each with the same unit and count: more units means more area. With different units, change to one unit first: a bigger unit gives a smaller count. The units of area are the square centimetre (cm², a square 1 cm a side) and the square metre (m², a square 1 m a side): books and stamps in cm², floors and walls in m².
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
A desk top holds exactly 7 storybooks of the same size laid flat, and each cover is 19 small squares big. How many small squares is the desk top?
Show the answer and working
Answer: 133 small squares
19 squares a book, so 7 books are 7 × 19 = 133 squares.
Example 2
A table top can be covered exactly by 15 red cards, or exactly by 19 blue cards. Each red card is bigger than each blue card.
True or false?
Show the answer and working
Answer: True
For the same table, the fewer cards it takes, the bigger each card: compare 15 and 19.
Example 3
Sheet A is laid on sheet B. A covers B completely, with some of A sticking out. Which sheet has the bigger area?
- A. The same
- B. A
- C. Can't tell
- D. B
Choose the right answer
Show the answer and working
Answer: B. A
A covers all of B with some to spare, so A has the bigger area.
Practise it in the game →Perimeter and area · Free to start, unlimited questions, no download