- 1. Write 40 as a product of its prime factors.
A) 22 X 3
B) 24 X 7
C) 32 X 5
D) 23 X 5
E) 52 X 3
- 2. Write 72 as a product of its prime factors.
A) 53 X 32
B) 23 X 32
C) 23 X 35
D) 22 X 33
E) 24 X 32
- 3. Write 240 as a product of its prime factors.
A) 22 X 3 X 7
B) 23 X 32
C) 53 X 32
D) 24 X 7
E) 25 X 3 X 5
- 4. Find the highest common factor (HCF) of 60 and 114
A) 6
B) 4
C) 8
D) 3
E) 9
- 5. Find the lowest common multiple (LCM) of 120 and 150
A) 750
B) 450
C) 400
D) 250
E) 600
- 6. Find the highest common factor (HCF) of 84 and 120
A) 23
B) 9
C) 7
D) 12
E) 8
- 7. Find the lowest common multiple (LCM) of 70 and 56
A) 280
B) 300
C) 210
D) 200
E) 250
- 8. Two buses, bus A and bus B, both use the same bus stop. Bus A runs every 10 minutes. Bus B runs every 14 minutes. Both buses are at the bus stop at 11 am. What time will both buses next both be at the bus stop.
A) 2:30pm
B) 2:10pm
C) 12:30pm
D) 12:10pm
E) 1:10pm
- 9. Light A flashes every 8 seconds. Light B flashes every 20 seconds. Both lights flash at the same time. Work out how long it will take for both lights to flash at the same time again.
A) 40 seconds
B) 30 seconds
C) 20 seconds
D) 45 seconds
E) 48 seconds
- 10. Write down the highest common factor (HCF) of 648 and 540.
A) 108
B) 120
C) 85
D) 100
E) 90
- 11. Find the lowest common multiple (LCM) of 648 and 540.
A) 2340
B) 210
C) 3240
D) 3210
E) 5430
- 12. Find the lowest common multiple (LCM) of 12, 15 and 18
A) 100
B) 200
C) 150
D) 180
E) 120
- 13. Light A flashes every 5 seconds. Light B flashes every 6 seconds. Light C flashes every 7 seconds. All three lights flash at the same time. Work out how long it will take for all three lights to flash at the same time again.
A) 150 seconds
B) 40 seconds
C) 200 seconds
D) 210 seconds
E) 140 seconds
- 14. Find the highest common factor (HCF) of 72, 90 and 126.
A) 20
B) 24
C) 12
D) 18
E) 10
- 15. Kenny is thinking of two numbers greater than 10. He says: ”The highest common factor (HCF) of my two numbers is 7 The lowest common multiple (LCM) of my two numbers is 84” Write down the two numbers that Kenny is thinking of.
A) 21 and 30
B) 21 and 24
C) 12 and 28
D) 20 and 28
E) 21 and 28
- 16. A red light flashes every 6 seconds. A yellow light flashes every 4 seconds. They both flash at the same time. After how many seconds will they next both flash at the same time?
A) 210 seconds
B) 24 seconds
C) 45 seconds
D) 20 seconds
E) 10 seconds
- 17. A blue light flashes every 8 minutes while a pink light flashes every 54 minutes. Both lights flash together at 2pm. When is the next time that both lights will flash together again?
A) 5:26pm
B) 5:30pm
C) 5:36pm
D) 6:36pm
E) 4:36pm
- 18. Mary is organising a charity hot dog sale. There are 18 bread rolls in each packet. There are 15 hot dogs in each packet. Mary buys exactly the same number of bread rolls as hot dogs. What is the smallest number of each packet that Mary can buy?
A) 5 packets of bread rolls and 9 packets of hot dogs
B) 8 packets of bread rolls and 4 packets of hot dogs
C) 5 packets of bread rolls and 6 packets of hot dogs
D) 10 packets of bread rolls and 6 packets of hot dogs
E) 6 packets of bread rolls and 5 packets of hot dogs
- 19. Trains leave Bristol to Cardiff every 15 minutes to London every 21 minutes A train to Cardiff and a train to London both leave Bristol at 11am. At what time will a train to Cardiff and a train to London next leave Bristol at the same time?
A) 12:10pm
B) 5:30pm
C) 12:35pm
D) 12:45pm
E) 12:30pm
- 20. The Highest Common Factor (HCF) of two numbers is 6. The Lowest Common Multiple (LCM) of the same numbers is 60. What are the two numbers?
A) 16 and 30
B) 12 and 24
C) 12 and 40
D) 20 and 30
E) 12 and 30
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