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Number Trail Grade 3 / Week 04 / Tuesday
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Week 04 · Missing numbers

Tuesday

Unknowns in division
// Unknowns, turn-arounds and break-aparts
⏱ about 15 min

Tuesday: Unknowns in division

Samantha shares her acorns with 3 young squirrels.

"Each of them got 5 acorns," she says.

"How many acorns did I start with?"

Bennie writes: ? ÷ 3 = 5.

"This time the total is the unknown," he says.

Samantha flicks her tail. "Can multiplying help again?"

"It always helps," says Bennie with a smile.

Learn it: multiply to find the total

? ÷ 3 = 5 asks: what total, shared by 3, gives 5 each?

3 shares of 5 is 3 × 5 = 15.

So the unknown is 15, and 15 ÷ 3 = 5.

Three equal groups with five dots in each group

The unknown can be in any spot.

24 ÷ ? = 6 asks: what times 6 makes 24?

The answer is 4, because 4 × 6 = 24.

The equal sign can come first, too.

5 = ? ÷ 3 means the same as ? ÷ 3 = 5.

FIND THE TOTAL
  • Read the question.
  • Tap your answer.
Three equal groups with five dots in each group? ÷ 3 = 5
? ÷ 4 = 8
? ÷ 7 = 6
5 = ? ÷ 3
FIND THE DIVISOR
  • Read the question.
  • Tap your answer.
24 ÷ ? = 6
36 ÷ ? = 4
40 ÷ ? = 8
63 ÷ ? = 9
MIXED UNKNOWNS
  • Read the question.
  • Tap your answer.
9 = ? ÷ 8
42 = 6 × ?
81 ÷ 9 = ?
20 ÷ ? = 2
SentenceTrue or false?
3 × 5 = 15?
32 ÷ 4 = 8?
63 ÷ 7 = 10?
72 ÷ 8 = 9?
WHY THIS EXERCISE7 × 9 = 63, so 63 ÷ 7 = 9.
SOLVE ? ÷ 3 = 5
  • Think about how Bennie solves it.
  • Tap the steps in order.
1First
2Next
3Then
4Last
Try it
Ask a grown-up to hide some spoons in 4 cups, 3 in each cup.
Do not peek! Write ? ÷ 4 = 3.
Find the unknown with a multiplication fact.
Then count the spoons to check.
◇ MYSTERY NUMBER WITH A GROWN-UP
Your grown-up thinks of a division, like 18 ÷ 3 = 6.
They hide one number and say the rest, like "? ÷ 3 = 6."
You find the hidden number with a multiplication fact.
Switch jobs and play five rounds.

Super sleuthing! Tomorrow we turn factors around.

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