Ray's New Primary Arithmetic · Lesson XL · Unit 5: Multiplication
40. Multiplying by 2
Goal: Your child knows the 2 times table by heart, both ways round, and uses it in story problems.
You'll need
- About 20 small counters: dried beans, buttons, pennies or pebbles (the book suggests marbles, beans or pebbles)
- A slate, small whiteboard or paper and pencil
What's in the book
The table from "1 times 2 is 2" to "10 times 2 are 20", with each fact also turned around, then about nine story problems on prices and quantities. The first has a worked solution.
The lesson, step by step
Warm up
Count by 2s as far as your child can go. Then ask three facts from the earlier tables.
Build a few facts
Make 3 groups of 2 beans: "3 times 2 are 6." Then 4 groups, then 5.
Both ways round
Show that 3 times 2 and 2 times 3 give the same total: turn the rows of beans sideways.
Read the table
Read the table on the book page together, then alone.
Cover and recall
Cover the answers and ask the facts out of order.
Story problems
Read the problems aloud. They go like this:
When peaches are selling at 2 cents each, how much will 2 peaches cost?
Frank bought 2 plums, at 3 cents each: how much did they cost?
Your child answers in a full sentence, as the worked solution does: "The melons cost 2 times 8 cents, which are 16 cents."
Wrap up
Your child writes the table from memory, as far as they can.
Afterwards
Say the table aloud each day, then answer five facts out of order. Move on when it comes instantly.
Tip
Times 2 is the same as doubling, and the same as counting by 2s.