Week 05 · Divide by multiplying
Tuesday
Fact families
// Missing factors, fact families and tens
⏱ about 15 min
Tuesday: Fact families
At the second challenge stop, Bruce holds up three cards.
They say 6, 8 and 48.
"Make as many true facts as you can with these numbers," he says.
Bennie lines up the cards on a flat rock.
"Two times facts and two division facts," he says.
"The same three numbers make a family."
Bruce flicks his tufted ears. "Four facts! Can you find them all?"
Learn it: three numbers, four facts
This rectangle has 6 rows of 8 squares.
6 × 8 = 48 and 8 × 6 = 48.
48 ÷ 6 = 8 and 48 ÷ 8 = 6.
If you know one fact, you know all four.
FINISH THE FACT FAMILY
- Read the question.
- Tap your answer.
63 ÷ 7 = ?
63 ÷ ? = 7
? × 7 = 63
9 × ? = 63
WHICH FACT DOES NOT BELONG?
- Read the question.
- Tap your answer.
Which fact is not in the 4, 9, 36 family?
Which fact is not in the 5, 7, 35 family?
Which fact is not in the 3, 8, 24 family?
Use a fact you know
Some facts are easier to remember.
8 × 7 is double 4 × 7. 4 × 7 = 28, and 28 + 28 = 56.
9 × 6 is 10 × 6 take away one 6. 60 - 6 = 54.
USE A FACT YOU KNOW
- Read the question.
- Tap your answer.
4 × 7 = 28. What is 8 × 7?
10 × 6 = 60. What is 9 × 6?
5 × 7 = 35. What is 6 × 7?
4 × 6 = 24. What is 8 × 6?
FACTS WITHIN 100
- Read the question.
- Tap your answer.
9 × 7 = ?
6 × 6 = ?
81 ÷ 9 = ?
64 ÷ 8 = ?
7 × 7 = ?
Check each fact with the family 7, 8, 56 or 6, 8, 48.
| Sentence | True or false? |
|---|---|
| 8 × 6 = 6 × 8 | ? |
| 48 ÷ 8 = 6 | ? |
| 56 ÷ 7 = 9 | ? |
| 7 × 9 = 63 | ? |
WHY THIS EXERCISE56 ÷ 7 is 8, because 7 × 8 = 56.
Try it
Find an egg carton, or make 2 rows of 6 cups.
Count the spaces: 2 rows of 6.
Say all four facts for 2, 6 and 12.
Count the spaces: 2 rows of 6.
Say all four facts for 2, 6 and 12.
Draw a rectangle of 3 rows of 7 squares. Write its four facts.
You found whole families! Tomorrow we multiply by tens.