2. 127 449 367 313 137 199 919 303153 415 57187 127 313 X 199 449 367 X 137 919 X 129 XX X X X X X X XX 213 93 111 453 1 666183 Identify the prime numbers in the grid below. There are 7 to find.

3. To use the prime factorisation of a number Use a Venn diagram to sort information Use prime factorisations to find the lowest common multiple of two numbers

4. 48 = 2 x 2 x 2 x 2 x 3 60 = 2 x 2 x 3 x 5 48 60 2 2 2 2 3 3 22 5 Multiply the numbers in the overlap to get the HCF Multiply all the numbers in the Venn diagram to get the LCM. HCF = 2 x 2 x 3 = 12 LCM = 2 x 2 x 3 x 2 x 2 x 5 = 240 Find the HCF and LCM of the following: 24 and 30 36 and 50 16 and 72

5. Using prime factors to find the HCF and LCM

6. Main Task Page 8, Exercise 1D Starting Q4 Securing Q5-7 Applying Q8/9

7. 60 294 60 = 2 × 2 × 3 × 5 294 = 2 × 3 × 7 × 7 2 2 3 5 7 7 HCF of 60 and 294 =2 × 3 x 7 = 35 LCM of 60 and 294 = 2 × 2 × 2 x 3 × 3 x 5 x 7 × 7 = 17640 Spot the three mistakes

8. 60 294 60 = 2 × 2 × 3 × 5 294 = 2 × 3 × 7 × 7 2 2 3 5 7 7 HCF of 60 and 294 =2 × 3= 6 LCM of 60 and 294 = 2 × 5 × 2 × 3 × 7 × 7 =2940 Correct method