Multiplication Division and using Money Doubling and Halving

Multiplication, Division and using Money Doubling and Halving Objectives Day 1 Y 1: Double numbers up to 20. Y 2: Understand doubling and halving as inverses; Double and halve 2 -digit numbers. Day 2 Y 1: Halve even number to 20. Y 2: Double and halve 2 -digit numbers. © hamilton-trust. org. uk 1 Year 1/2

Multiplication, Division and using Money Doubling and Halving Short Mental Workouts Day 1 Doubling numbers to 10 Day 2 Odd/even numbers © hamilton-trust. org. uk 2 Year 1/2

Multiplication, Division and using Money Doubling and Halving Short Mental Workout Doubling numbers to 10 © hamilton-trust. org. uk 3 Year 1/2

Multiplication, Division and using Money Doubling and Halving Short Mental Workout Odd/even numbers © hamilton-trust. org. uk 4 Year 1/2

Multiplication, Division and using Money Doubling and Halving Day 1 Y 1: Double numbers up to 20. Y 2: Understand doubling and halving as inverses. Double and halve 2 -digit numbers. © hamilton-trust. org. uk 5 Year 1/2

Day 1 Y 1: Double numbers up to 20. Y 2: Understand doubling and halving as inverses. Double and halve 2 -digit numbers. How many on 2 strings? How many beads on the string? Half of 40 is 20. 40 ÷ 2 = 20. Double 20 is 40. 20 × 2 = 40. Remember that doubling is the same as multiplying by 2, and halving is the same as dividing by 2. Halving is the opposite, or inverse, of doubling. © hamilton-trust. org. uk 6 Year 1/2

Day 1 Y 1: Double numbers up to 20. Y 2: Understand doubling and halving as inverses. Double and halve 2 -digit numbers. Write the answers on your whiteboards… Y 2: Can you write the corresponding halving fact? Y 1: What is double 6? Y 2: Can you write the corresponding halving fact? Y 1: What is double 7? © hamilton-trust. org. uk 7 Year 1/2

Day 1 Y 1: Double numbers up to 20. Y 2: Understand doubling and halving as inverses. Double and halve 2 -digit numbers. Think, pair, share… What has the ‘Mystery Machine’ done? It has doubled 30. Double 30 is 60. © hamilton-trust. org. uk 8 Year 1/2

Day 1 Y 1: Double numbers up to 20. Y 2: Understand doubling and halving as inverses. Double and halve 2 -digit numbers. Think, pair, share… What has the ‘Mystery Machine’ done this time? It has halved 80. Half of 80 is 40. © hamilton-trust. org. uk 9 Year 1/2

Day 1 Y 1: Double numbers up to 20. Y 2: Understand doubling and halving as inverses. Double and halve 2 -digit numbers. Think, pair, share… What number has been doubled to give 62? Remember: doubling and halving are opposites! Half of 62 is 31, so 31 was the input number. © hamilton-trust. org. uk 10 Year 1/2

Day 1 Y 1: Double numbers up to 20. Talk towe your When double a partner. number, we add the Whatamount do we again, same mean by e. g. doubling? 2 doubled is 2 + 2 =4 We can check that with cubes… 2+2=4 What would double 3 be? 3+3=6 © hamilton-trust. org. uk 12 Year 1/2

Day 1 Y 1: Double numbers up to 20. How can we find the double of 10? We add another 10 … 10 + 10 = 20 double 10 is 20 © hamilton-trust. org. uk 13 Year 1/2

Day 1 Y 1: Double numbers up to 20. What about double 11? Double 11 is 22 Can you see why? Double 10 is 20. © hamilton-trust. org. uk Double 1 is 2. 14 Year 1/2

Day 1 Y 1: Double numbers up to 20. What about double 12? Double 12 is 24 Can you see why? Double 10 is 20. © hamilton-trust. org. uk Double 2 is 4. 15 Year 1/2

Day 1 Y 1: Double numbers up to 20. What is double 13? Double 13 is 26 Can you see why? Double 10 is 20. © hamilton-trust. org. uk Double 3 is 6. 16 Year 1/2

Day 1 Y 1: Double numbers up to 20. What is double 14? Double 14 is 28 Can you see why? Double 10 is 20. © hamilton-trust. org. uk Double 4 is 8. 17 Year 1/2

Challenge © hamilton-trust. org. uk 18 Year 1/2

Multiplication, Division and using Money Doubling and Halving Day 2 Y 1: Halve even numbers to 20. Y 2: Double and halve 2 -digit numbers. © hamilton-trust. org. uk 19 Year 1/2

Day 2 Y 1: Halve even numbers to 20. Y 2: Double and halve 2 -digit numbers. It’s like sharing the number between 2. If. Talk I hadto 4 your sweets, and I needed to halve them, I partner. What do to weshare them would need mean by 2 halving? into equal piles. Half of 4 is 2. 4 sweets Can you see why? © hamilton-trust. org. uk 20 Year 1/2

Day 2 Y 1: Halve even numbers to 20. Y 2: Double and halve 2 -digit numbers. What is half of 10? Half of 10 is 5 Can you see why? 10 issweets What double 5? Doubling is the opposite of halving! © hamilton-trust. org. uk 21 Year 1/2

Day 2 Y 1: Halve even numbers to 20. Y 2: Double and halve 2 -digit numbers. What is half of 6? Half of 6 is 3 Can you see why? 6 sweets What is double 3? Doubling is the opposite of halving! © hamilton-trust. org. uk 22 Year 1/2

Day 2 Y 1: Halve even numbers to 20. Y 2: Double and halve 2 -digit numbers. What is half of 14? Half of 14 is 7 Can you see why? 14 sweets What is double 7? Doubling is the opposite of halving! © hamilton-trust. org. uk 23 Year 1/2

Day 2 Y 1: Halve even numbers to 20. Y 2: Double and halve 2 -digit numbers. What happens if we try to find half of 9, an odd number? Y 2: Why haven’t we chosen any odd numbers to halve so far? 1 sweet is always 9 sweets left over when we halve an odd number! © hamilton-trust. org. uk 24 Year 1/2

Day 2 Y 1: Halve even numbers to 20. Y 2: Double and halve 2 -digit numbers. What method of halving numbers is quicker than sharing? We can use the doubles facts we know to help us. If we know double 8 is 16… …then we know the opposite, that half of 16 is 8. This is called a bar model. © hamilton-trust. org. uk 25 Year 1/2

Day 2 Y 1: Halve even numbers to 20. Y 2: Double and halve 2 -digit numbers. This bar model has 12 small blocks on the top. How many cubes would be in each half? Talk to your partner. What number, when it is doubled, is 12? © hamilton-trust. org. uk What doubles fact can we use to help us? Double 6 is 12. Half of 12 is 6. 26 Year 1/2

Day 2 Y 1: Halve even numbers to 20. Y 2: Double and halve 2 -digit numbers. How many cubes would be in each half? What doubles fact can we use to help? Talk to your partner. What number, when it is doubled, is 14? © hamilton-trust. org. uk Double 7 is 14. Half of 14 is 7. 27 Year 1/2

Day 2 Y 1: Halve even numbers to 20. Y 2: Double and halve 2 -digit numbers. This number is a bit Let’s think back to the bigger than those partitioning in the last we’ve tried to halve so lesson… far. 24 Half of 20 is 10. Half of 4 is 2. Let’s recombine these separate parts: 10 + 2. And nowhalve let’s Let’s halve the first. ones. the tens © hamilton-trust. org. uk So, half of 24 is 12 28 Year 1/2

Day 2 Y 1: Halve even numbers to 20. Y 2: Double and halve 2 -digit numbers. This number is a bit Let’s think back to the bigger than those partitioning in the last we’ve tried to halve so lesson… far. 28 Half of 20 is 10. Half of 8 is 4. Let’s recombine these separate parts: 10 + 4. Let’s And nowhalve let’s the tens halve the first. ones. © hamilton-trust. org. uk So half of 28 is 14 29 Year 1/2

Challenge © hamilton-trust. org. uk 30 Year 1/2

Challenge © hamilton-trust. org. uk 31 Year 1/2

Multiplication, Division and using Money Doubling and Halving Well Done! You’ve completed this unit. Objectives Day 1 Y 1: Double numbers up to 20. Y 2: Understand doubling and halving as inverses. Double and halve 2 -digit numbers. Day 2 Y 1: Halve even numbers to 20. Y 2: Double and halve 2 -digit numbers. © hamilton-trust. org. uk 32 Year 1/2

Problem solving and reasoning questions Year 1 Draw lines from each double to its matching half: Double 3, double the answer, and double the answer! Halve 28 and halve the answer. Is the answer more than 10? © hamilton-trust. org. uk 33 Year 1/2

Problem solving and reasoning questions Year 2 Write the missing halves/ doubles. Diagram 1: Diagram 2: Diagram 3: Poppy starts at 56 and keeps halving. What is the first 1 -digit number she reaches? © hamilton-trust. org. uk 34 Year 1/2

Problem solving and reasoning answers Year 1 Draw lines from each double to its matching half: Double 3, double the answer, and double the answer! 24 3 doubled three times: 3 -6 -12 -24. Halve 28 and halve the answer. Is the answer more than 10? No. It is 7. © hamilton-trust. org. uk 35 Year 1/2

Problem solving and reasoning answers Year 2 Write the missing halves/ doubles. Diagram 1: Diagram 2: Diagram 3: Poppy starts at 56 and keeps halving. What is the first 1 -digit number she reaches? 7 Half of 56 = 28 Half of 28 = 14 Half of 14 = 7. Check children are correctly partitioning 2 -digit numbers to help with halving. © hamilton-trust. org. uk 36 Year 1/2