1. Un jumble these letters to make our key words!
Starter
Un jumble these letters to make our key words!
Highest
steghih
Common
moncom
Factors
actfors

2. BAT write a number as a product of primes BAT Find the HCF of two numbers

3. HCF 1
Sammy has 45 sweets and 30 chocolates to share equally amongst his friends
What is the largest number of friends that can get the same number of sweets and chocolates? Explain your answer
Answer =15
Explain 15 is the Highest common factor (HCF)
Discuss definition of HCF – highest number that goes into what you have

4. HCF 2
Jane has to organise party bags for her daughters birthday. She has 84 balloons and 126 sweets
If she puts equal amounts of balloons and sweets in the party bags, how many party bags can she make?
2x3x7x2= x3x7x3= HCF = 2x3x7 = 42

5. Samantha has two pieces of cloth. One piece is 72 inches wide and the
HCF 3
Samantha has two pieces of cloth.
One piece is 72 inches wide and the
other piece is 90 inches wide. She wants to cut both pieces into strips of equal width that are as wide as possible.
How wide should she cut the strips?
Find HCF of 72 and 90
HCF of 72 and 90 = 18
She should cut the strips 18 inches wide

6. What is the largest number of pirates that can get equal shares?
HCF 4
Blackbeard has 420 pieces of gold and 560 pieces of silver. He decides to share this treasure equally amongst his pirate crew
What is the largest number of pirates that can get equal shares?
Answer 140
Students may need calculators to get this one or may see it straight away
Extension method – using prime products (not really suitable for Cd ability students but some may reach)
420 = (2x2x5x7)x3 560 = (2x2x5x7)x2x2 140 = 2x2x5x7

7. HCF 5
A box measures 24 cm by 18 cm by 15 cm. The box is to be filled with cubes of equal size.
What is the length of the side of the largest cube that could be used to fill the box?
Find HCF of and 15
HCF of and 15 = 3
A cube with side 3cm

8. TRY THESE: Find the HCF
MODEST ONES
TRICKIER ONES
24 and 40
42 and 63
44 and 242
24 and 60
48 and 60
66 and 48
56 and 35
42 and 54
70 and 175
35 and 75
50 and 70
240 and 540
28 and 48
75 and 105
20 and 56
42 and 98
Answers:

9. BAT write a number as a product of primes
Summary
You should be able to:
BAT write a number as a product of primes
BAT Find the HCF of two numbers
One thing I have learned is …
One thing I can improve is …

10. END