Short Blocks

Maths Year 2 Autumn More Addition and Subtraction (B)

Each unit has everything you need to teach a set of related skills and concepts.

Add/subtract multiples of 10 (suggested as 2 days)

Planning and Activities

Day 1 Teaching
Use Spider on the 1-100 grid to demonstrate how we can add multiples of 10 to a 2-digit number, e.g. 46 + 30. Stress that Spider doesn’t have to count in 1s! Repeat, using Spider to subtract multiples of 10, e.g. 63 – 40.
Group Activities
-- Children play a game using Spider on the 1-100 grid to rehearse adding and subtracting multiples of 10.

Day 2 Teaching
Use a bead string to demonstrate how we can add multiples of 10 to a 2-digit number. Note that the 1s digit does not change. Repeat to show how we can subtract multiples of 10.
Group Activities
Use the in-depth problem-solving investigation ‘The Number Square!’ from NRICH as today’s group activity. Or, use these activities:
-- Children use a 100-beaded line to add or subtract 20, 30, 40 or 50. They choose their own calculations to solve.
-- Some children investigate patterns when adding and subtracting given multiples of 10 to 2-digit numbers.

You Will Need

  • 1-100 grids (see resources)
  • Small cubes
  • Plastic Spider
  • ‘Add or Subtract 10s’ cards (see resources)
  • ‘Spider counters’ (see resources)
  • Small circles of card
  • 0-100 bead strings
  • Large beaded number line
  • Additional activity sheets (see resources)

Mental/Oral Maths Starters

Day 1
Count on and back in 10s, with 100 grid (pre-requisite skills)

Day 2
Count on and back in 10s, using a bead bar (pre-requisite skills)

Worksheets

Day 1
Children practise adding and subtracting multiples of 10 to/from 2-digit numbers using a 1-100 grid and Spider.

Day 2
Children use a beaded line to solve addition and subtraction calculations. Some will find the missing number in a number sentence.

Mastery: Reasoning and Problem-Solving

  • Complete this grid:
+20
54
6797
  • Explain what Bill has done wrong in his homework:
54+40=84
76-30=73
23+50=28
64-40=20
  • Choose a number to write in the first empty box:
    ☐ + 20 – 30 + 10 = ☐
    Do the calculation. Make an observation about the answer.
    Repeat with a different starting number.
    Explain what is happening.


In-depth Investigation: The Number Square!
Focus on strategies involving adding/subtracting multiples of 10 to put numbers back in the correct place on the 100-grid, e.g. 14 + 40 = 54, 87 - 60 = 27. The Number Square! from nrich.maths.org.

Extra Support

Spider's Workout
Adding and subtracting 10 using a 1-100 grid