Ray's New Practical Arithmetic · Art. 31 (1–21) · Unit 4: Multiplication
15. Multiplying by one figure
Goal: Your child multiplies large numbers by a multiplier up to 12, carrying correctly.
You'll need
- The book
- A slate, small whiteboard or scrap paper
- A notebook and pencil
What's in the book
The rule for a multiplier not over 12, then 21 numbered problems about cloth, houses, land and goods, with answers. The rule and the first problems fall on p. 42, which is missing from this scan; use another copy or read them aloud from this guide.
The lesson, step by step
Warm-up
Mental: 4 × 23? 3 × 123? 5 × 40?
The rule
Read:
Write the multiplicand, with the multiplier under it, and draw a line beneath.
Begin with units; multiply each figure of the multiplicand by the multiplier, and carry as in addition.
Work the book example together
Read:
How many yards of cloth are there in 3 pieces, each containing 123 yards?
3 × 3 = 9, 3 × 2 = 6, 3 × 1 = 3, so 369 yards.
Guided practice
Do the next one together:
What will 2 houses cost at $231 each?
Then one with carrying, from further down the list.
Independent practice
Your child does problems 3 to about 15. Finish the rest another day.
Check
Answers are printed. When an answer is wrong, look first at the carrying.
Wrap-up
Mental: 9 × 12? 11 × 11? 12 × 12?