Teaching and Group Activities for Understanding
Day 1 Teaching
Children make 24 and 32 using place value cards. Model this process using Place value ITP. Demonstrate how to add the two 10s and the two 1s and then recombine: 30 + 20 = 50 and 2 + 4 = 6. Total = 56. Also show how to count on in 10s and 1s (start at 32; add 20 then 4): 32..42..52..53..54..55..56. Which strategy do you prefer? Ask children to work out 73 + 21, 52 + 37, 54 + 26. Model 47 + 35 using partitioning, to show what happens when the ones add to more than ten.
-- Add two 2-digit numbers from number cards, noting methods used.
-- Add two 2-digit numbers from dice, explaining reasons for methods used.
Day 2 Teaching
Remind children of the two methods they used in Day 1 for adding: partitioning and counting on. Practise adding two 2-digit numbers, allowing children to choose their preferred method. Ask two children using different methods to explain why they used the method they chose.
Use the in-depth problem-solving investigation ‘Diagonal hundreds’ as today’s group activity.
Or, use these activities:
-- Add two 2-digit numbers from spinners, choosing appropriate methods.
-- Add two 2-digit numbers, suggesting the method to be used and devising ‘top tips’ for method selection.