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Unit 3 - Lesson 19 - Grade 3: Illustrative Mathematics

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16 Questions
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Grade 3 Unit 3
Lesson 19: Situations and Equations
CC BY 2021 Illustrative Mathematics®
Grade 3 Unit 3
Lesson 19: Situations and Equations
CC BY 2021 Illustrative Mathematics®
Lesson: Situations and Equations

Notice and Wonder: The Unknown (Warm Up)

1.

What do you notice?

2.

What do you wonder?

Mai’s Beads

Part 1

Match each diagram with a situation. Be ready to explain your reasoning.
3.

Situation 1: Mai had 104 beads. She bought two packs of beads and now she has 124 beads. How many beads were in each pack?

4.

Explain your reasoning.

5.

Situation 2: Mai had some beads. She bought 2 more packs of beads and each pack has 10 beads in it. Now she has 124 beads. How many beads did Mai have before?

6.

Explain your reasoning.

7.

Situation 3: Mai had 104 beads. She bought 2 more packs of beads and each pack has 10 beads in it. How many beads does she have now?

8.

Explain your reasoning.

Part 2

Match each equation with a letter for the unknown quantity to a situation in Part 1.
9.

104 + 2 x 10 = n

10.

104 + (2 x n) = 124

11.

n + 10 + 10 = 124

Represent, Solve, Explain

Kiran is setting up a game of mancala. He has a jar of 104 stones.

From the jar, he takes 3 stones for each of the 6 pits on his side of the board.

12.

Write an equation to represent the situation. Use a letter for the unknown quantity.

13.

Solve the problem. Explain or show your reasoning.

14.

Explain how you know your answer makes sense.

Cool Down: How Many Beads?
Andre has 196 beads. He uses 48 beads to make a craft. Then he gives 30 beads to a friend. How many beads does Andre have left?
15.

Write an equation with a letter for the unknown quantity to represent this situation.

16.

Solve the problem. Explain or show your reasoning.