### Teaching and Group Activities for Understanding

**Day 1 Teaching**

Use bar models to support writing addition and subtraction facts. Use number balances to model equalities; explore pairs to 13.

**Further Teaching with Y4**

Add 2-digit numbers in addition grids using an appropriate mental strategy.**Group Activities: T with Y4**

Y3 -- Explore and write equalities (‘balancing’ sums).

Y4 -- Investigate ways in which digits can be arranged in an addition grid to give ascending totals, totals <100 and totals >100.

**Day 2 Teaching**

Use a 100 bead bar to demonstrate how 5 + 3 is similar to 15 + 3, 25 + 3, 35 + 3, …105 + 3, 125 + 3, 245 + 3, 845 + 3. Repeat for 17 + 7, 27 + 7, 37 + 7, 47 + 7, using ‘Target the 10’ strategy. Show on beaded, landmarked and empty number lines.

**Group Activities: T with Y3**

Y3 -- Identify mystery numbers by spotting patterns when adding 1-digit to 2-digit numbers.

Y4 -- Repeatedly add a 1-digit number to a 3-digit number; describe and explain any patterns in the ones digits.

**Day 3 Teaching**

Use the bead bar to show how 5 – 2 is similar to 15 – 2, 25 – 2, 35 – 2, 105 – 2, 145 – 2, 475 – 2. Repeat for 24 – 7, 34 – 7, etc. Show on beaded, landmarked and empty lines.**Group Activities: T with Y3**

Y3 – Play a dice or card game to practise subtracting 1-digit from 2-digit numbers.

Y4 -- Dice game subtracting from 3-digit numbers.