Ray's New Primary Arithmetic · Lesson XXXV · Unit 4: Subtraction
35. Review of subtraction
Goal: Your child answers mixed "less" facts up to 19 quickly.
You'll need
- A slate, small whiteboard or paper and pencil
What's in the book
A long drill of mixed facts in the book's wording, such as "How many are 12 less 4? 12 less 8? 13 less 6?". The first has a worked solution.
The lesson, step by step
Drill in short bursts
Ask five facts from the page, then stop and praise. Then five more.
Sort the slow ones
Write any slow facts on cards. They become the warm-up for the next few days.
Check with adding
For 13 less 6, ask: 6 and what make 13?
Afterwards
Keep the cards of slow facts and run through them each day.