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Number Trail Grade 3 / Week 05 / Monday
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Week 05 · Divide by multiplying

Monday

Division is a missing factor
// Missing factors, fact families and tens
⏱ about 15 min

Monday: Division is a missing factor

Bruce the Bobcat straightens his headband at the first challenge stop.

"Here are 32 acorns," he says. "Pack them in bags of 8."

"How many bags will you need?"

Bennie the Bear sets down his basket of apples.

"This is a division problem," he says.

"But we can solve it with multiplication."

"We ask, 8 times what makes 32?"

Learn it: think of the missing factor

32 ÷ 8 = ? asks how many groups of 8 make 32.

We can write the same question as 8 × ? = 32.

Bennie counts by eights: 8, 16, 24, 32. That is 4 eights.

So 8 × 4 = 32, and 32 ÷ 8 = 4.

Four equal groups with eight dots in each group

The missing factor is the quotient.

Every division fact hides a times fact inside it.

FIND THE MISSING FACTOR
  • Read the question.
  • Tap your answer.
8 × ? = 32
6 × ? = 30
7 × ? = 21
9 × ? = 54
4 × ? = 28
DIVIDE BY THINKING OF A TIMES FACT
  • Read the question.
  • Tap your answer.
32 ÷ 8 = ?
30 ÷ 6 = ?
54 ÷ 9 = ?
28 ÷ 4 = ?
45 ÷ 5 = ?
WHICH FACT HELPS?
  • Read the question.
  • Tap your answer.
Which times fact helps you find 42 ÷ 7?
Which times fact helps you find 24 ÷ 3?
Which times fact helps you find 63 ÷ 9?
Which times fact helps you find 40 ÷ 8?
COUNT THE GROUPS
  • Read the question.
  • Tap your answer.
Six equal groups with five dots in each groupThese 30 dots are in groups of 5. How many groups?
Eight equal groups with three dots in each groupThese 24 dots are in groups of 3. How many groups?
An acornBruce has 36 acorns. He packs bags of 4. How many bags?
STEPS FOR 56 ÷ 8
  • Think about how Bennie divides.
  • Tap the steps in order.
1First
2Next
3Then
4Last
SentenceTrue or false?
24 ÷ 6 = 4?
35 ÷ 5 = 6?
72 ÷ 9 = 8?
18 ÷ 3 = 6?
WHY THIS EXERCISE35 ÷ 5 is 7, because 5 × 7 = 35.
Try it
Take 24 small things, like beans or buttons.
Make groups of 6.
Count the groups.
Say the times fact: 6 × 4 = 24.
Draw 20 dots in groups of 4. Write the division fact.

Great thinking! Tomorrow Bruce shows us fact families.