Same area, different perimeter, and tens
Answers are for parents and teachers.
1
Find three rectangles with an area of 16 square cm and the perimeter of each one.
16 by 1: 34 cm. 8 by 2: 20 cm. 4 by 4: 16 cm.
2
A rectangle has a perimeter of 18 cm and a width of 4 cm. Find its length and its area.
The two widths make 8 cm. 18 − 8 = 10 cm for the two lengths, so the length is 5 cm. The area is 5 × 4 = 20 square cm.
3
63 sweets are packed in bags of 9. How many bags are there?
63 ÷ 9 = 7 bags. Check: 7 × 9 = 63.
4
Find 6 × 70 and 9 × 30.
6 × 7 = 42, so 6 × 70 = 420. 9 × 3 = 27, so 9 × 30 = 270.
5
A school hall has 7 rows with 60 chairs in each row. How many chairs are there?
7 × 6 = 42, so 7 × 60 = 420 chairs.