M2.2.1 For the adult
Adding in your head
Can I add 46 and 29 without writing anything down?
What this chapter teaches
Add by splitting each number into tens and ones, or add a near ten and take the extra back. A common mistake is to add the extra on instead: 46 + 29 is 46 + 30 − 1.
Three questions to ask
There is no one right wording. Listen for the idea.
- How could you work out 46 + 29 in your head?
- Why do you take 1 back after adding 30 to 46?
- How would you work out 35 + 48 without writing anything down?
After the chapter, the learner can
- Add two 2 digit numbers by adding the tens, then the ones
- Work out 46 + 29 as 46 + 30 − 1
What they copy into their notebook
Split each number into tens and ones. Add the tens. Add the ones. Join them. Or add a near ten and take the extra back. 46 + 29 = 46 + 30 − 1 = 75.