Lesson Plan
Denver Public Schools
1
Student Activity
Name:
Lesson
Period:
The Mystery Bags Game
Objective: Describe the general process for solving for unknown quantities in a problem.
PART 1 — You’re the King
The game sounds easy, but it can get difficult for the king. See if you can win the mystery bags game in the various situations
described here by figuring out how much gold is in each mystery bag.
On a separate sheet of paper, explain how to play the game for each of the 7 scenarios below. Explain how you know you are
correct. Your explanation should consist of a combination of words, pictures, or diagrams that show what is going on. For full
credit, you must write in complete sentences.
1.
2.
3.
4.
5.
6.
Three mystery bags are on one side of the balance, and 51 ounces of lead weights are on the other side.
One mystery bag and 42 ounces of weights are on one side, and 100 ounces of weights are on the other side.
Eight mystery bags and 10 ounces of weights are on one side, and 90 ounces of weights are on the other side.
Three mystery bags and 29 ounces of weights are on one side, and 4 mystery bags are on the other side.
Eleven mystery bags and 65 ounces of weights are on one side, and 4 mystery bags and 100 ounces of weights are on the
other side.
The king wants to win easily all of the time, without calling you in. Therefore, your task is to describe in words a procedure by
which the king can find out how much is in a mystery bag in any situation.
Try out your procedure on the following problem. Does it work? If not, revise it.
7.
Twelve mystery bags and 4 ounces of weights are on one side, and 5 mystery bags and 18 ounces of weights are on the other
side.
PART 2 — You’re the Jester
Now, you are the jester. For each equation below, do two things.
1. Describe how the jester must place the mystery bags and lead weights so the equation will be a representation of the
situation.
2. Find the weight of one mystery bag and explain how you got the answer.
a. 5M + 24 = 51 + 2M
b. 43M + 37= 56M + 24
c. 12M + 15= 5M + 62
Denver Public Schools
2
Homework
Name:
Lesson
Period:
The Mystery Bags Game
Find the weight of one mystery bag and explain how you found
your answer. The M stands for mystery bag.
1.
Simplify the equations below.
6.
32 + (5)2
7.
50  5 * 23
8.
Write the rule for the following table.
72 = 5M + 7
Weight:
Explanation:
2.
5M = 3M + 12
Weight:
Explanation:
3.
21M = 19M + 120
Weight:
x
y
Explanation:
0
6
1
9
2
12
3
15
4
18
5
21
Rule:
4.
M + 16 = 8M + 2
Weight:
Explanation:
5.
Three mystery bags and 18 ounces of weights are on one
side of the scale, and 4 mystery bags and 17 ounces of
weights are on the other side of the scale.
Weight:
9.
Fill in the table for the rule y = 2x + 5
x
y
0
1
2
3
4
Explanation:
Denver Public Schools
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