Maths Year 2 Spring More Addition and Subtraction

Day 1 Teaching
Display a pen priced 45p. Say you will buy this and pay with 50p. Use a 0–50 line to show how we can count up from 45p to 50p to find change. Show how we can cross out 0–45 and see what is left. Repeat with a sharpener costing 48p. Show that if you spent 2p, you would get 48p change. Repeat for 43p.
Group Activities
-- Find change from 50p when buying items that cost forty-something pence.
-- Find change from 10p.

Day 2 Teaching
Show a problem. Matthew had £17 and spent £15 on an art set. How much money has he left? Mark 17 on a 0–20 beaded line. Emphasise that Matthew spent £15, so cross out 0–15. Explain that he has 2 left. Show lines of 15 and 17 on ITP Difference to reinforce. Repeat with a spend of £14.
Group Activities
Use the in-depth problem-solving investigation ‘Combining Coins’ from NRICH as today’s group activity.
Or, use this activity:
-- Find the difference between two 2-digit numbers by counting up.
-- Decide whether to count up or back to find change in pounds.

• Pen labelled with the price of 45p
• Sharpener labelled 43p
• 0–50p penny line (see resources)
• ‘Finding change from 50p’ sheet (see resources)
• Lines of 15 and 17 on ITP Difference (see resources)
• Additional activity sheets (see resources)
• 10–30 number cards

Day 1
Bonds to 10 (pre-requisite skills)

Day 2
Add to next 10 (pre-requisite skills)

Day 1
Calculate and write subtraction sentences for change from 10p, 20p or 50p.

Day 2
Calculate how much pocket money is left by finding the difference; decide whether to count up or back to find a difference.

• Complete each sentence by writing the missing numbers.
  47p + ☐ = 50p
  ☐ + 39p = 50p
  50p = ☐ + 45p
• Write the missing number in each bar diagram:
  Diagram 1

Diagram 2

Diagram 3

• Caitlyn has spent £15. She has £6 left. How much did she have to start with?

In-depth investigation: Combining Coins
Is it always possible to make a total using every number of coins between the minimum and the maximum possible numbers? Combining Coins (first activity) from nrich.maths.org.

Dinosaur Day
Finding change from 20p

Day 1 Teaching
Ask children how we could solve 65 – 24. Do we count back in ones? Draw out that we can count back 20, and then subtract 4. Say we use a number fact: 5 – 4. Repeat for 85 – 24. Draw on the landmarked line, and also as an empty number line jotting. Repeat for 85 – 30, 85 – 33, 77 – 33, 96 – 32.
Group Activities
-- Play a card game to subtract two 2-digit numbers and draw accurate empty number lines.
-- Subtract two 2-digit numbers: identify answers that will be less than 50.

Day 2 Teaching
Show 85p as 50p, three 10ps and a 5p coin. A banana is 33p. Move away three 10p coins and count back in 10s. Now we take away 3. What is 5 take away 3? Remove the 5p coin and replace with a 2p coin. Repeat with similar subtractions.
Group Activities
Use the in-depth problem-solving investigation ‘Build it Up’ from NRICH as today’s group activity.
Or, use this activity:
-- Find missing numbers in subtraction calculations.

• 0 to 100 landmarked line (see resources)
• Red and yellow cards to write on
• Beads
• ‘Subtracting 2-digit numbers by counting back on a beadstring’ sheets (see resources)
• 0 to 100 beaded lines (see resources)
• Blank cards to write on
• Cubes
• Coins – real and for display on the IWB
• Sticky notes

Day 1
Using subtraction facts (pre-requisite skills)

Day 2
Using addition and subtraction facts (pre-requisite skills)

Day 1
Subtract pairs of 2-digit numbers, recording jottings on beaded, landmarked or empty number lines.

Day 2
Solve and create subtraction word problems.

• Write the steps in this subtraction to help Zoe.
  56 – 34
  Count back in tens.
  56 ___ ____ ____
  Subtract 4 ____
  56 – 34 = ____
• Mia has 69p, Tom has 88p and Padma has 37p.
  Each child spends 34p.
  How much does each have left?
• Explain how you would subtract 55p from 98p.
  Complete this subtraction grid

• Mark Jo’s homework. Write the correct answers.
  75 - 23 = 98
  86 - 32 = 55
  67 - 24 = 43
  64 - 42 = 20
  

In-depth Investigation: Built it Up
Can children find all the ways to get 15 at the top of a triangle of numbers? A good opportunity to explore the relationship between addition and subtraction. Build it Up from nrich.maths.org.

Spot the Pattern
Using number facts and patterns to subtract 1-digit numbers from 2-digit numbers, e.g. 6 - 3, 16 - 3, 26 - 3, 36 - 3... 96 - 3

Day 1 Teaching
Say you have 52p and spend 47p. Mark 52p on a 0–£1 penny line. Explain: We can count up to find a difference. Mark on 47p, and cross out pennies up to 50p, then to 52p: 3p + 2p is 5p left. Repeat for £63 – £56, hopping £4 to £60, then another £3 to find the £7 difference.
Group Activities
-- Discover how much money is left by calculating differences using a penny line.
Day 2 Teaching
Show a toy frog and agree a name. Explain that maths Frog helps us subtract by hopping up the number line to find a difference. Model how Frog hops from 37 to 45 on the bead bar to solve 45 – 37. Repeat several times with other problems on beaded lines.
Group Activities
-- Calculate the difference between two 2-digit numbers by counting up with Math Frog.
-- Play ‘snatch the match’: subtract two 2-digit numbers by counting up with Maths Frog.

Day 3 Teaching
Write 53 - 47 on the board and read it as 53 subtract 47. Model counting back; then use Frog to find the difference. Compare the two strategies. Use Frog to solve 54 – 48, 23 – 17 and 65 – 54.
Group Activities
-- Solve subtractions using beaded, landmarked or empty number lines.
-- Suggest the subtraction by watching Maths Frog complete jumps on a bead bar.

Day 4 Teaching
Show how solve 62p – 47p using a 0–£1 penny line. Cross out up to 47p. Then demonstrate drawing 3 hops: 47 to 50, then 50 to 60 and 60 to 62. Write 85 – 68 and show how Maths Frog can help us count up. Repeat with 61 – 47 on a landmarked line.
Group Activities
Use the ‘Frog’s Busy Day’ in-depth problem-solving investigation below as today’s group activity.
Or, use this activity:
-- Solve subtractions of 2-digit numbers with answers greater than 10.

Day 5 Teaching
Discuss how we may want to solve 53p – 11p and 60p – 47p in different ways. The first can easily be done by counting back. The second may be more easily solved with maths frog. Repeat to choose a different strategy for 62 – 25 and 67 – 25.
Group Activities
-- Investigate an efficient method for subtracting (counting up or back).

• 0–£1 penny lines and 0–£1 landmarked lines (see resources)
• ‘How much money is left?’ sheet (see resources)
• ‘Finding change’ sheet (see resources)
• Coins
• Pen with a price level of 59p, other items with price labels of 55p, 57p, 58p, 56p
• Maths Frog (toy)
• 100-bead bar
• Additional activity sheets (see resources)
• Dice (some 1–8 and some 1–6)
• Counters
• Whiteboards and pens

Day 1
Pairs to 10 (pre-requisite skills)

Day 2
Add to the next 10 (pre-requisite skills)

Day 3
Identify 2-digit numbers on a landmarked line (pre-requisite skills)

Suggested for Day 4
Count on and back in tens (simmering skills)

Suggested for Day 5
Telling time to the quarters (simmering skills)

Day 1
Find how much money is left over when children buy a drink by finding the difference.

Day 2
Use Frog (counting up) to solve subtractions.

Day 3
Subtract 2-digit numbers by counting up.

Day 4
Use number lines to find the difference by counting up.

Day 5
Choose an efficient strategy to solve subtractions.

• Find the change from 50p if I spend 38p using a 0–50 penny line.
• Draw Frog’s hops on a number line to show the difference between 43 and 36.
  Draw Frog’s hops on a number line to show 65 – 58.
• Tell Frog how many hops he will need to do for each of these subtractions:
  a) 45 – 38
  b) 62 – 45
  c) 71 – 65
  d) 34 – 18
  Now use Maths Frog to help you solve each one.
  Were you right about the number of hops each time?
• Explain which method you would choose to do each of these subtractions:
  47 – 24
  63 – 47
  74 – 64

In-depth Investigation: Frog's Busy Day
Children look for numbers which have a difference of 5 using Frog to help.

Tall Towers
Finding a small difference