AO elaboration and other teaching resources
Solve problems by finding the prime factors of numbers.
Number Framework Stage 8
Problem: “Gerry builds rectangles out of 6 square tiles. Find all the ways of building rectangles with these tiles.”
“Repeat for 7 tiles.”
Discuss why 7 is called a prime number and 6 is not.
(Answer: There is only one way of building 7 namely 7 tiles in a single row. Whereas 6 can also be built as 2 rows of 3.)
Examples: By building rectangles out of tiles determine which of these numbers are prime and which are not: 5 8 11 9 15 13 16.
Understanding Number Properties:
Explain why 2 is the only even prime number.
Using Number Properties
Problem: “7 has factors 1 and 7, and 7 is a prime number. 6 has factors 1, 2, 3, and 6, and 6 is not a prime number. Complete this general rule: If we look at all the factors of a number, we know when it is a prime number if..".