Ray's New Practical Arithmetic · Arts. 35–39 · Unit 5: Division
19. What division is
Goal: Your child explains division as sharing and as repeated subtraction, names its parts, and reads the three ways of writing it.
You'll need
- The book
- A slate, small whiteboard or scrap paper
- A notebook and pencil
What's in the book
Short sharing problems, definitions of division, divisor, dividend and quotient, division as repeated subtraction, three ways to show division, and the division table.
The lesson, step by step
Warm-up
Do the book's first problems aloud:
If you divide 6 apples equally between 2 boys, how many will each boy have?
How many times 2 in 6? Ans. 3.
The definition
Read:
Division is the process of finding how many times one number is contained in another.
SayThe divisor is what we divide by, the dividend is what we divide, and the quotient is the answer.
Repeated subtraction
Read:
Division may be termed a short method of making many subtractions of the same number.
Work the example: A boy has 8 cents: how many lemons can he buy, at 2 cents each? 8 − 2 − 2 − 2 − 2: four times, so 4 lemons.
Three signs
Read:
Division is indicated in three ways:
Show 12 ÷ 3, 3)12, and the fraction form with 12 over 3. All mean 12 divided by 3.
The remainder
Read:
The remainder is always less than the divisor
Ask: If you share 14 cents among 3, each gets 4 and 2 are left. Why can't the remainder be 3 or more?
Wrap-up
Read through the division table together, then quick-fire: 56 ÷ 8, 72 ÷ 9, 84 ÷ 12, 45 ÷ 5.