Maths Year 1/2 Summer Multiplication and Division (B)

Day 1
Use two bead strings to show double 20. Remind children that doubling and halving are inverses. Stress that doubling is multiplying by 2 and halving is dividing by 2. Use ‘Mystery Machines’ (resources) alongside base-10 equipment to generate and discuss halves/doubles.
Further Teaching with Y1
Use base-10 equipment to model the partitioning, doubling and recombining steps in doubling 10, 11, 12, 13 and 14.
Group Activities: T with Y2
Y1 -- Double handfuls of cubes.
-- Play a double numbers card game, using numbers up to 15.
Y2 -- Reason about the missing number or operation in ‘Mystery Machines’.
-- Play a double and half pairs game.

Day 2
Explain that halving is sharing the number between two. Demonstrate by sharing four sweets between two children. Repeat with other even numbers up to 20. Note that odd numbers need to be treated differently as there is always one left over. Display a bar model to show double 8 is 16. Use this to halve 16. Repeat for other numbers. Use base-10 equipment to support partitioning, halving and recombining.
Group Activities: T with Y2
Y1 Use the in-depth problem-solving investigation ‘Halving Chains’ as today’s group activity.
Or, use these activities:
-- Decide if numbers are odd or even, then halve the even numbers.
Y2 – Double and halve 2-digit numbers.

• Cubes
• ‘Mystery Machine’ Sheets A, B and C (see resources)
• Mini-whiteboards and pens
• ‘Doubling recording sheet’ (see resources)
• ‘Doubling cards’ Sheets 1–3 (see resources)
• ‘Doubling recording sheet’ (see resources)
• Number cards 1–40
• Blank cards
• ‘Mystery Machine doubling and halving’ Sheets 1 and 2 (see resources)
• Blank ‘Mystery machine doubling and halving’ sheets (see resources)
• Calculators
• Sticky notes
• ‘Halving’ (see resources)
• ‘Halving recording sheet’ (see resources)
• Base-10 equipment, e.g. Dienes blocks or number shapes
• 20-bead (or 100-bead) strings

Day 1
Doubling numbers to 10

Day 2
Odd/even numbers

Day 1
Y1: Double numbers to 15; record as an addition sentence.
Double numbers to 21; record as an addition sentence.
Y2: Reason about the missing number or operation in doubling/halving Mystery Machines.

Day 2
Y1: Halve numbers to 22 or 32.
Y2: Halving investigation.

Y1

• Draw lines from each double to its matching half
  14 6
  12 10
  16 7
  28 8
  20 13
  24 14
  26 12
• Double 3, double the answer, and double the answer.
  Halve 28 and halve the answer. Is the answer more than 10?
  
  Y2
• Write the missing halves/doubles (see download).
• Poppy starts at 56 and keeps halving. What is the first 1-digit number she reaches?

In-depth investigation: Halving chains
Children investigate which numbers from 1 to 20 (Y1) or 1 to 50 (Y2) will give the longest halving chain (each 'link' must be a whole number).

Y1: Copycat
Finding doubles from double 1 to double 10
AND
Be Fair!
Halving even numbers up to 10

Y2: Double your money
Doubling 11 to 20
AND
Fair or not fair
Halving even numbers from 20 to 30

Day 1
Sit children in a circle and place 4 bags of 5 buttons in the middle. How many buttons in total? Model counting in 5s: 5, 10, 15, 20. Write on the board: 4 × 5 = 20 (4 lots of 5 is 20). Repeat with 3 bags of 5 buttons, 6 bags of 5 buttons, then 8 bags of 2 counting bears.
Group Activities: T with Y1
Y1 -- Calculate multiplications by creating multiple ‘sets of’.
-- Create multiple ‘sets of’ counting bears.
Y2 -- Investigate which number of cubes (11, 12, 15, 20 and 24) will make the biggest number of sets of equal height towers.

Day 2
Build 3 towers of 10 cubes. How many cubes? Use ‘clever counting’ to count in 10s to establish 30. Repeat to find 5 towers of 10 cubes. Then show 40 cubes on the floor and ask how many towers of 10 cubes can be made from these. Repeat for towers of 5 using 15 cubes.
Further Teaching with Y2
Write 15 ÷ 5 on the board. We can read this as I have 15, how many 5s can I make? Explain that we can also write this as a multiplication with a hole in it: □× 5 = 15. Repeat for other divisions.
Group Activities: T with Y2
Y1 -- Build towers of the same height and find the total.
-- Calculate how many towers can be built using a given number of cubes.
Y2 -- Rewrite divisions as ‘multiplications with holes’, use facts/clever counting to calculate answers.

Day 3
I have five 2p coins in my purse. How much money do I have altogether? Count in 2s to 10p. Record: 5 × 2p = 10p. I have 8p in my purse. All of the coins are 2p coins. How many 2p coins are there? On a 0–50p penny line, circle groups of 2p up to 8p. Repeat with similar problems, including how many 5ps are in 36p, and discuss the 1p left over, the remainder.
Group Activities: T with Y1
Use the in-depth problem-solving investigation ‘Clapping Times’ from NRICH as today’s group activity.
Or, use these activities:
Y1 -- Count in 2s to find how many 2p coins are needed to make a given amount.
-- Ring sets of 2 on a penny line to calculate how many 2ps are in a purse.
Y2 -- Use 5p coins to explore remainders after division by 5.

• Buttons and counting bears (or other small objects)
• Cubes
• Transparent bags
• ‘Multiplication sets’ (see resources)
• Bags of small objects
• Flipchart and pens
• Mini-whiteboards and pens
• Number cards 2–10, cards with numbers 11, 12, 15, 20 and 24, 5 and 10 cards
• ‘0 to 50 beaded line’ (see resources)
• ‘0 to 50 beaded lines’ (see resources)
• 1–10 dice
• ‘Towers Table’ (see resources)
• ‘Problem cards’ (see resources)
• ‘Divisions’ (see resources)
• 2p coins, 5p coins, purse
• ‘0–50p penny line’ (see resources)
• ‘0 to 20 penny lines’ (see resources)
• ‘0 to 50p penny lines’ (see resources),
• ‘How many 2p coins?’ Sheets 1 and 2 (see resources)
• ‘Money amounts cards’ (see resources)

Day 1
Count in 5s

Day 2
Count in 10s

Day 3
Count in 2s

Day 1
Y1: Solve ×2 and ×5 multiplications using cubes.
Y2: Solve multiplication word problems.

Day 2
Y1: Calculate how many towers of 2, 5 or 10 can be made using given numbers of cubes.
Y2: Draw hops on beaded lines to solve divisions, then complete corresponding multiplications AND Find the missing numbers in a series of multiplications and divisions.

Day 3
Y1: Calculate how many 2p or 5p coins are in a purse from a given total amount.
Y2: Choose numbers to divide by 5; score points if there is a remainder.

Y1

• True or false?
  - 40p is eight 5p coins.
  - If we have 10 gloves, we can make 5 pairs.
  - 12 is 8 groups of 2.
  - 35 beads can be made into 7 necklaces, each with 5 beads.
• How many 10p coins are in my purse if I have 60p? (I only have 10p coins)
• How many 5p coins are in my purse if I have 25p? (I only have 5p coins)
• How many 2p coins are in my purse if I have 26p? (I only have 2p coins)
  

Y2

• How many hops of 5 in:
  20? 35? 50?
• How many 2s in:
  16? 20? 24?
• Explain why 20 ÷ 5 = ☐ can also be written as ☐ × 5 = 20.
• Write the missing numbers:
  ☐ × 2 = 12 ☐ × 2 = 20
  ☐ × 5 = 30 ☐ × 10 = 60
• Divide each number by 5. Divide the answer by 2:
  30, 20, 50, 40
  What could you have divided by to calculate these in one step?

In-depth investigation: Clapping Times
If you count from 1 to 20 and clap more loudly on the numbers in the 2 times table, which numbers will be loud? Combine different tables. When do you both clap? Clapping Times from nrich.maths.org

Y1: Good Dog
Using grouping to divide by 2, then 5

Y2: Ring the Twos
Carrying out early division (in 2s)