Four digits and more

What this chapter teaches

Each column holds one digit. When a column makes 10 or more, write the last digit and carry the rest. A list of numbers can carry 2 or more. A top number with zeros needs an exchange along the zeros, one place at a time.

Three questions to ask

There is no one right wording. Listen for the idea.

1. What do you do when the ones column adds up to 25?
2. Why can we not write 14 in the ones column?
3. How would you work out 5 002 − 2 457, and where does the first exchange come from?

After the chapter, the learner can

• Add and take away 4 digit numbers in columns
• Add a list of three or four numbers