Maths Year 2 Autumn More Addition and Subtraction (A)

Day 1 Teaching
Use a 20 bead frame to rehearse bonds to 10 and 20. Then use these facts to spot pairs to 10 and 20 when adding three numbers, e.g. 13 + 8 + 7 or 6 + 7 + 4. Encourage children to spot the bond to make the addition easy.
Group Activities
Use the in-depth problem-solving investigation ‘Getting the Balance’ from NRICH as today’s group activity. Or, use these activities:
-- Children work in pairs to use number facts in adding three or four numbers less than 20.
Day 2 Teaching
Write ■ + ▲ = 10 on f/chart. There are 2 mystery numbers here. What could they be? If square is 8, ask what triangle is? What if square was 1? So there are lots of possible answers. Repeat for different pairs of mystery numbers including subtraction: 20 - ■ - ▲ = 15.
Group Activities
-- Children learn how to find the mystery number in a number sentence using known number facts.

• Bean bag
• 20 bead frame (2 rows of 10 beads with whiteboard)
• 0-20 cards
• ‘Slidy box’ cards
• 20 bead strings
• Activity sheet of mystery number sentences (see resources)

Day 1
Pairs to 10 (pre-requisite skills)

Suggested for Day 2
Adding 3 numbers (simmering skills)

Day 1
Children complete a number search to find number bonds to 20.

Day 2
Children complete a number search to find 3 numbers that add up to 20.

• Complete these bar diagrams:
  Diagram 1

Diagram 2

• Write a sentence with a missing number. It must also include the number 20.
• Correct Tina’s work. What mistake is she making?
  13 + 17 = 20
  20 – 14 = 16
  20 – 11 = 19

In-depth Investigation: Getting the Balance
Can you hang weights in the right place to make the scale balance? Getting the Balance from nrich.maths.org.

Give me 5...or 6 or 7
Finding pairs with a total of 5, 6 and 7

Day 1 Teaching
Show 5 beads & 3 more on 1-100 bead bar. We all know 5 add 3! Show 15 & 3 more. Point at 5 + 3 beads in one colour. Repeat for 25 + 3, 35 + 3… 95 + 3. These are really easy - we don’t need to count on. Model on beaded line and landmarked line. Repeat for 9 – 4, 19 – 4, 29 – 4, 99 – 4.
Group Activities
-- Children use known number facts to solve addition and subtraction problems.
Day 2 Teaching
Add a single digit to a 2-digit number by bridging multiples of ten using a bead bar. Show 28 and model adding 5 beads. Once we know 8 + 5 is 13, it’s easy. 18 + 5= 23, 28 + 5 = 33, 38 + 5 = 43, etc. Repeat for other additions using beaded and landmarked lines.
Group Activities
Use the in-depth problem-solving investigation ‘Secret Number’ from NRICH as today’s group activity.
Or, use these activities:
-- Children use a landmarked or beaded line to solve addition problems using known facts.

Day 3 Teaching
Subtract a single digit from a 2-digit number by bridging multiples of 10 using a bead bar. Start with 20-2, 30-2 etc. Then show 34 – 5, 44 – 5 etc. using beaded and landmarked lines. Repeat for other subtractions.
Group Activities
-- Children use a landmarked or beaded line to solve subtraction problems using known facts.

• 100 bead bar
• Bead strings
• Flip chart
• 0-100 beaded line
• 0-100 landmarked line

Suggested for Day 1
Pairs to 20 (simmering skills)

Day 2
Complements to multiples of 10 (pre-requisite skills)

Day 3
Subtraction facts for 10 (pre-requisite skills)

Day 1
Children complete additions and subtractions that follow a pattern, encouraging them to use known number facts.

Day 2
Children rehearse adding a single-digit to a 2-digit number.

Day 3
Children practise subtracting a single-digit from a multiple of 10 and 2-digit numbers.

• Write three additions which include a 2-digit number ending in 5, and the number 7.
• Complete each sentence by writing the missing numbers.
  43 + ☐ = 48
  36 + 6 = ☐
  ☐ – 4 = 60
  27 + 7 = ☐
  ☐ – 3 = 72
• Tom has 66 cards. He needs to get 72 to complete his set. How many more does he need?
• Complete this grid.

In-depth Investigation: Secret Number
Annie and Ben are playing a game with a calculator. What was Annie's secret number? Adapt numbers used to ensure addition by bridging. Secret Number from nrich.maths.org.

Sum Patterns
Using pattern and number bonds to work out related additions, e.g. 3 + 2 = 5, so 13 + 2 = 15, 23 + 2 = 25, 33 + 2 = 35...

Day 1 Teaching
Use a 20-bead frame to show 5 + 2 on lower bar, hiding all other beads behind the whiteboard. What is 5 add 2? Slide top 10 beads across and discuss how we now have 15 add 2. Tell children that we only needed to know one number fact (5 + 2) to find 15 + 2. Recall ‘Spider’ from earlier in term, for adding 10. Refer to 1-100 grid.
Use the bead frame to show further additions and subtractions. If we know what 5 - 2 is, then we can use this fact to find 15 – 2.
Group Activities
Use the ‘Cross Additions’ in-depth problem-solving investigation below as today’s group activity.
Or, use these activities:
-- Solve additions and subtractions using number facts.
-- Apply knowledge of number facts to add and subtract.

Day 2 Teaching
Write 35 + 3, 27 - 5, 30 + 5, 46 + 6, 27 - 7, 56 + 3, 99 – 3. Draw out using number fact 5 + 3 = 8 for first question. Stick card under heading Number fact. How about 30 + 5? Use place value! Stick card under a heading Place value. Discuss which use PV, which use a number fact. Sort cards into 2 sets. Answer some.
Group Activities
-- Sort calculations according to the strategy used to solve them.
-- Investigate equality using an on-screen interactivity.

• 20-bead frame
• 1-100 number grid (see resources)
• Number fact cards (see resources)
• Multilink cubes or Numicon shapes
• Calculations on cards or on IWB
• ‘Sorting calculations’ (see resources)
• Paper strips

Day 1
Number facts (pre-requisite skills)

Suggested for Day 2
Pairs to 20 (simmering skills)

Day 1
Children show how to solve addition and subtraction problems using number facts.

Day 2
Children solve addition and subtraction calculations to play a game of 4 in a row with a partner or to complete an individual challenge.

• Fact families. Write 4 number sentences that link each ‘trio’ of numbers:
  3, 8, 5
  27, 2, 25
• Number Balance from nrich.maths.org
  Can you hang weights in the right place to make the ‘equaliser’ balance?
• Fill in the missing numbers:
  62 + ☐ = 69
  48 = 43 + ☐
  37 + ☐ = 41
  ☐ – 5 = 74
• Write the missing number in each diagram
  Diagram 1

Diagram 2

Diagram 3

In-depth Investigation: Cross Additions
Using number facts including pairs to 10 children find totals of 5 numbers less than 10 to give different totals.

Sums say the answers!
Using place value to add, e.g. 20 + 4 = 24

Day 1 Teaching
Show a bead bar and demonstrate adding 8 and 5 by doing 8 + 2 + 3 (‘bridging’) to land on a multiple of 10. Call this strategy ‘Target the 10s’ or ‘T10’ for short. Model 18 + 5, 28 + 5… Repeat for 6 + 7, 16 + 7, 26 + 7, etc. Use the bead bar to show the pattern. Model recording strategy (see detailed plan).
Group Activities
-- Children develop understanding of bridging 10 when adding a 1-digit number to a 2-digit number using beaded lines or landmarked lines.

Day 2 Teaching
Colour multiples of 10 on a 1-100 grid in red. Point these numbers out on the 0-100 bead bar. Write 37 + 6. Ask a child to point to 37. Recall that we can use number facts to help us (37 + 6 = 37 + 3 + 3). Repeat for other additions, crossing a 10s number and not crossing a 10s number, e.g. 33 + 4.
Group Activities
Use the ‘Pyramids’ in-depth problem-solving investigation below as today’s group activity.
Or, use these activities:
-- Children sort and solve additions by bridging 10, using 1-100 number grids, beaded or landmarked lines.

Day 3 Teaching
Write 32 - 6. Use a 1-100 grid with multiples of 10 shaded. Point at 32. If we count back 6, we will cross a multiple of ten (30). Count back 2 then 4 more. 32 - 6 = 26. Be explicit that this the opposite (inverse) of the T10 strategy they have been using for addition. Repeat, using grid to find 45 - 7.
Show: 22 - 5, 27 - 5, 38 - 4, 33 - 4, 22 - 5, 27 - 6, 48 - 6, 53 – 7. Which will cross a multiple of 10?
Group Activities
-- Children sort and solve subtractions by bridging 10, using 1-100 number grids, beaded or landmarked lines.

• 100 bead bar
• Target the 10s calculation cards (see resources)
• Sheets of 0-100 beaded lines (see resources)
• Target the 10s recording sheet (see resources)
• Additional activity sheets (see resources)
• 1-100 number grid with 10s shaded red (see resources)
• 5-9 digit cards
• Addition calculations on cards or IWB

Day 1
Complements to multiples of 10 (pre-requisite skills)

Suggested for Day 2
Place value (simmering skills)

Day 3
Subtraction facts for 10 (pre-requisite skills)

Day 1
Train Journey. Children add single digit numbers to keep a running total of the number of passengers on a train.

Day 2
Being a teacher. Children mark addition problems that have been solved. Children to use their chosen method for each addition.

Day 3
Match subtraction calculations to correct answers by counting back or using number facts.

• Write the next multiple of 10.
  45 -> ☐
  63 -> ☐
  38 -> ☐
  Write how many you add to get there.
• The answer is 53. What ‘T10’ addition did do you do?
• Circle the calculations that cross a multiple of 10.
  34 + 8
  53 + 5
  78 – 5
  18 + 4
  26 + 7
  66 – 5
  Explain how you know.
• The answer is 67. What subtraction did do you do that crossed 70? Is that the only possibility?

In-depth Investigation: Pyramids
Children explore addition patterns in pyramids. They arrange numbers in a pyramid to create the largest and smallest possible totals.

What's the gap?
Saying the next 10s number; Finding how many to the next 10s number, e.g. 36 + ? = 40