1. PRIME NUMBERS AND FACTOR TREES

2. DEFINITION Prime Number – An integer whose only factors are 1 and itself 2, 3, 5, 7,11, 13, 17, 19

3. DEFINITION Factor - a whole number that divides exactly into another whole number, with no remainder. eg. 30 ÷ 6 = 5 Factor

4. DEFINITION The factors of a number can be found using factor pairs. One of the pairs may be a single number which multiplies by itself. Factor Pair eg. 4 x 6 = 24

5. DEFINITION A factor tree shows the prime factors of a composite number

6. Prime Factor Tree for 60 Write 60 at the top of the page 60 60 = prime number 2 x 30 2 2 30 15 35 30 = prime number 2 x 15 15 = prime number 3 x prime number 5 60 can be written as 2 x 2 x 3 x 5 multiplied together

7. Prime Factor Tree for 72 Write 72 at the top of the page 72 72 = prime number 2 x 36 2 2 36 18 29 36 = prime number 2 x 18 18 = prime number 2 x 9 72 can be written as 2 x 2 x 2 x 3 x 3 multiplied together 33 9 = prime number 3 x prime number 3

8. Draw the factor tree for: 24

9. 4 6 2223 Prime Factors 2 x 2 x 2 x 3 have now been found.

10. 24 2 12 26 23 Prime Factors 2 x 2 x 2 x 3 have now been found.

12. In pairs Complete the “Factor Tree Game”