🤖 RobotsGrade 4Reading: grades 5-6RoundingAdditionSubtractionMultiplicationDivision

The Gearopolis CPU Caper

Someone hacked the main server at the Gearopolis Cyber Lab and scrambled the blueprints! We must decode the system logs to identify the rogue bot responsible before they escape with the core CPU.

Suspects

Possible suspects

Cross off a row as each clue rules it out. On screen, tap a row.

21 of 21 still in play

Name	Primary Module	Secondary Tool	Battery Gauge	Wire Type	Reboot Switch
Volt Wire	Grapple Arm	Oil Injector	Digital Screen	Silver Cables	Freeze Ray
Axle Bolt	Rocket Boost	Radar Dish	Digital Screen	Silver Cables	Magnet Blast
Hover Disk	Plasma Shield	Solar Panel	Analog Meter	Silver Cables	Freeze Ray
Relay Switch	Rocket Boost	Micro Scanner	Digital Screen	Copper Wires	Freeze Ray
Quantum Core	Grapple Arm	Micro Scanner	Analog Meter	Silver Cables	Rust Spray
Turbo Vane	Laser Cutter	Oil Injector	Analog Meter	Copper Wires	Freeze Ray
Data Drive	Grapple Arm	Solar Panel	Digital Screen	Silver Cables	Freeze Ray
Iron Sprocket	Grapple Arm	Solar Panel	Analog Meter	Fiber Optics	Freeze Ray
Echo Node	Grapple Arm	Oil Injector	Analog Meter	Silver Cables	Freeze Ray
Gear Widget	Laser Cutter	Micro Scanner	Analog Meter	Silver Cables	Rust Spray
Beep Boop	Sonic Cannon	Oil Injector	Digital Screen	Silver Cables	Rust Spray
Vector Ray	Sonic Cannon	Radar Dish	Analog Meter	Copper Wires	Rust Spray
Zinc Plate	Plasma Shield	Welder Torch	Digital Screen	Silver Cables	Freeze Ray
Micro Switch	Sonic Cannon	Welder Torch	Digital Screen	Silver Cables	Rust Spray
Pixel Grid	Plasma Shield	Micro Scanner	Digital Screen	Silver Cables	Freeze Ray
Unit Zero	Grapple Arm	Welder Torch	Analog Meter	Silver Cables	Magnet Blast
Sensor Array	Rocket Boost	Welder Torch	Digital Screen	Fiber Optics	Freeze Ray
Oil Can	Plasma Shield	Radar Dish	Digital Screen	Silver Cables	Freeze Ray
Circuit Chip	Laser Cutter	Micro Scanner	Digital Screen	Fiber Optics	Magnet Blast
Kilo Watt	Sonic Cannon	Welder Torch	Digital Screen	Fiber Optics	Rust Spray
Nano Mesh	Sonic Cannon	Welder Torch	Analog Meter	Copper Wires	Freeze Ray

Clue 1

Rounding

The long-range radar screen only shows distance readouts rounded to the nearest ten.

Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.

110

130

3000

3700

4300

300

3000

110

3000

370

200

110

300

370

3000

500

1300

3000

9000

3000

3700

110

3700

7000

130

Round 114 to the nearest tenT

Round 540 to the nearest hundredA

Round 1,251 to the nearest hundredW

Round 3,480 to the nearest thousandE

Round 89 to the nearest tenO

Round 154 to the nearest hundredN

Round 333 to the nearest hundredU

Round 34 to the nearest tenD

Round 6,526 to the nearest thousandC

Round 8,563 to the nearest thousandL

Round 4,273 to the nearest hundredG

Round 70 to the nearest tenB

Round 131 to the nearest tenH

Round 366 to the nearest tenS

Round 3,705 to the nearest hundredR

0/15 letters found

Clue 2

Addition

The head engineer adds up total voltage spikes recorded in the security logs.

Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.

7447

7753

7781

8088

9379

8741

3242

7447

3242

6554

6037

7753

7157

4789

7781

5583

7753

7157

7753

7781

3242

2077

8741

4830

6037

9379

8088

2946 + 4501 =W

3980 + 2057 =R

5460 + 2628 =N

5796 + 2945 =S

4915 + 2866 =T

713 + 1364 =L

2713 + 3841 =B

2610 + 2220 =C

1785 + 3004 =H

4002 + 3751 =I

2721 + 4436 =G

1903 + 1339 =A

5642 + 3737 =E

2115 + 3468 =D

0/14 letters found

Clue 3

Subtraction

We calculate missing battery cells by subtracting remaining stock from original inventory.

Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.

5570

4429

1822

1045

3245

1045

1822

5570

1495

8132

4138

6462

2905

1045

1561

6462

2905

5082

4869

4455

1045

8132

4897

8132

8780

1045

4392

4869

8884 - 3314 =A

4665 - 1760 =W

7062 - 2924 =L

11036 - 4574 =O

5596 - 3774 =R

4766 - 311 =H

8922 - 4025 =U

9975 - 1843 =S

11669 - 2889 =P

9619 - 4537 =N

8195 - 3326 =T

2019 - 524 =Y

5368 - 939 =F

2592 - 1547 =E

3118 - 1557 =D

6154 - 1762 =C

7719 - 4474 =Z

0/17 letters found

Clue 4

Multiplication facts (1-12)

Mechanics inspect equal rows of storage crates holding extra server modules.

Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.

144

121

7 × 4 =T

8 × 8 =C

7 × 2 =F

7 × 11 =R

2 × 9 =D

10 × 3 =B

12 × 12 =H

2 × 8 =N

5 × 5 =A

9 × 8 =U

1 × 1 =S

3 × 7 =E

12 × 5 =P

11 × 1 =I

11 × 11 =V

5 × 1 =L

0/16 letters found

Clue 5

Division facts (1-12) — the last clue

The maintenance squad splits spare microprocessors evenly among repair droids.

First solve each problem. Then find each answer in the list below and cross that sentence out. One sentence will be left — that's exactly what the villain did!

Step 1 — solve these

21 ÷ 3 = ?

12 ÷ 6 = ?

100 ÷ 10 = ?

110 ÷ 10 = ?

10 ÷ 2 = ?

64 ÷ 8 = ?

36 ÷ 4 = ?

24 ÷ 6 = ?

132 ÷ 11 = ?

6 ÷ 6 = ?

15 ÷ 5 = ?

Step 2 — cross out the sentence with each answer

1.The villain ignites the rocket boost, then sparks the welder torch.

2.The villain deploys the plasma shield, then aligns the radar dish.

3.The villain deploys the plasma shield, then sparks the welder torch.

4.The villain ignites the rocket boost, then charges the solar panel.

5.The villain extends the grapple arm, then aligns the radar dish.

6.The villain extends the grapple arm, then squirts the oil injector.

7.The villain deploys the plasma shield, then activates the micro scanner.

8.The villain ignites the rocket boost, then aligns the radar dish.

9.The villain extends the grapple arm, then sparks the welder torch.

10.The villain extends the grapple arm, then charges the solar panel.

11.The villain deploys the plasma shield, then squirts the oil injector.

12.The villain fires the laser cutter, then squirts the oil injector.

Solve it

Name the culprit

Choose the one suspect left standing.

Answer Key — The Gearopolis CPU Caper

Culprit: Volt Wire (Grapple Arm · Oil Injector · Digital Screen · Silver Cables · Freeze Ray)

Clue 1 (Rounding): "THE ROGUE BOT DOES NOT USE A WELDER TORCH"
Round 114 to the nearest ten = 110 (T) · Round 540 to the nearest hundred = 500 (A) · Round 1,251 to the nearest hundred = 1300 (W) · Round 3,480 to the nearest thousand = 3000 (E) · Round 89 to the nearest ten = 90 (O) · Round 154 to the nearest hundred = 200 (N) · Round 333 to the nearest hundred = 300 (U) · Round 34 to the nearest ten = 30 (D) · Round 6,526 to the nearest thousand = 7000 (C) · Round 8,563 to the nearest thousand = 9000 (L) · Round 4,273 to the nearest hundred = 4300 (G) · Round 70 to the nearest ten = 70 (B) · Round 131 to the nearest ten = 130 (H) · Round 366 to the nearest ten = 370 (S) · Round 3,705 to the nearest hundred = 3700 (R)
Clue 2 (Addition): "WITNESS SAW A BRIGHT DIGITAL SCREEN"
2946 + 4501 = 7447 (W) · 3980 + 2057 = 6037 (R) · 5460 + 2628 = 8088 (N) · 5796 + 2945 = 8741 (S) · 4915 + 2866 = 7781 (T) · 713 + 1364 = 2077 (L) · 2713 + 3841 = 6554 (B) · 2610 + 2220 = 4830 (C) · 1785 + 3004 = 4789 (H) · 4002 + 3751 = 7753 (I) · 2721 + 4436 = 7157 (G) · 1903 + 1339 = 3242 (A) · 5642 + 3737 = 9379 (E) · 2115 + 3468 = 5583 (D)
Clue 3 (Subtraction): "A FREEZE RAY SLOWED DOWN THE SUSPECT"
8884 - 3314 = 5570 (A) · 4665 - 1760 = 2905 (W) · 7062 - 2924 = 4138 (L) · 11036 - 4574 = 6462 (O) · 5596 - 3774 = 1822 (R) · 4766 - 311 = 4455 (H) · 8922 - 4025 = 4897 (U) · 9975 - 1843 = 8132 (S) · 11669 - 2889 = 8780 (P) · 9619 - 4537 = 5082 (N) · 8195 - 3326 = 4869 (T) · 2019 - 524 = 1495 (Y) · 5368 - 939 = 4429 (F) · 2592 - 1547 = 1045 (E) · 3118 - 1557 = 1561 (D) · 6154 - 1762 = 4392 (C) · 7719 - 4474 = 3245 (Z)
Clue 4 (Multiplication facts (1-12)): "THE SUSPECT LEFT BEHIND SILVER CABLES"
7 × 4 = 28 (T) · 8 × 8 = 64 (C) · 7 × 2 = 14 (F) · 7 × 11 = 77 (R) · 2 × 9 = 18 (D) · 10 × 3 = 30 (B) · 12 × 12 = 144 (H) · 2 × 8 = 16 (N) · 5 × 5 = 25 (A) · 9 × 8 = 72 (U) · 1 × 1 = 1 (S) · 3 × 7 = 21 (E) · 12 × 5 = 60 (P) · 11 × 1 = 11 (I) · 11 × 11 = 121 (V) · 5 × 1 = 5 (L)
Clue 5 (Division facts (1-12)): surviving statement (box 6) → Volt Wire
21 ÷ 3 = 7 · 12 ÷ 6 = 2 · 100 ÷ 10 = 10 · 110 ÷ 10 = 11 · 10 ÷ 2 = 5 · 64 ÷ 8 = 8 · 36 ÷ 4 = 9 · 24 ÷ 6 = 4 · 132 ÷ 11 = 12 · 6 ÷ 6 = 1 · 15 ÷ 5 = 3

About this mystery

Grade level: Grade 4 math
Math topics: Rounding, Addition, Subtraction, Multiplication, Division
Reading level: grades 5-6
Theme: The Gearopolis CPU Caper — set in Gearopolis Cyber Lab
Format: Interactive online & printable worksheet with answer key
Solution: One unique, verified culprit among 21 suspects

More free printable math cases

4th grade worksheets Addition worksheets Subtraction worksheets Multiplication worksheets Division worksheets Rounding worksheets All worksheets →

The Great Beacon Heist

Grade 4

The Whisker Haven Golden Fish Caper

Grade 4

The Great Ridge Mystery

Grade 4

The Mystery of Misty Mountain Trail

Grade 4