🤖 RobotsGrade 4Reading: grades 3-4RoundingAdditionSubtractionMultiplicationDivision
The Great Cog Caper
A mischievous bot scrambled the blueprints for the city generator! Help Chief Engineer Sprocket follow the gear tracks and deduce who committed the malfunction.
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 | Gimmick Tool | Locomotion | Antenna Tilt | Wiring Color | System Vulnerability |
|---|---|---|---|---|---|
| Cipher Sam | magnet pulse | hover jets | left antenna bent | neon green wires | oil splashes |
| Piston Pam | frost beam | stealth cloak | right antenna bent | bright blue wires | oil splashes |
| Widget Bot | frost beam | stealth cloak | right antenna bent | bright blue wires | magnet traps |
| Radar Ray | frost beam | grapple arm | right antenna bent | neon green wires | magnet traps |
| Unit A1 | laser torch | hover jets | right antenna bent | neon green wires | magnet traps |
| Unit C3 | magnet pulse | stealth cloak | right antenna bent | glowing red wires | rust spray |
| Data Daisy | frost beam | hover jets | right antenna bent | neon green wires | magnet traps |
| Gizmo Gabe | sonic hum | turbo treads | right antenna bent | glowing red wires | magnet traps |
| Logic Leo | laser torch | hover jets | right antenna bent | neon green wires | oil splashes |
| Circuit Chip | plasma spark | grapple arm | right antenna bent | glowing red wires | magnet traps |
| Unit B2 | plasma spark | hover jets | left antenna bent | neon green wires | magnet traps |
| Beep Boop | laser torch | stealth cloak | right antenna bent | glowing red wires | oil splashes |
| Matrix Meg | laser torch | stealth cloak | right antenna bent | neon green wires | magnet traps |
| Servo Max | plasma spark | hover jets | left antenna bent | bright blue wires | magnet traps |
| Unit D4 | sonic hum | grapple arm | left antenna bent | bright blue wires | oil splashes |
| Tread Racer | magnet pulse | grapple arm | left antenna bent | glowing red wires | magnet traps |
| Gearhead Sprocket | laser torch | hover jets | right antenna bent | glowing red wires | magnet traps |
| Binary Ben | frost beam | grapple arm | right antenna bent | neon green wires | oil splashes |
| Sparky Axle | sonic hum | grapple arm | left antenna bent | bright blue wires | magnet traps |
| Bolts Dynamo | sonic hum | turbo treads | left antenna bent | bright blue wires | rust spray |
| Rust Catcher | sonic hum | hover jets | right antenna bent | neon green wires | magnet traps |
Clue 1
Rounding
The security display only shows rounded energy readings. Estimate the power level to unlock the first clue.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
T
20
90
170
3700
2900
200
200
4300
2900
430
1100
7000
170
3000
430
7000
T
20
290
3000
170
4300
230
50
4300
1700
1700
200
170
4300
50
130
Round 24 to the nearest tenT
Round 152 to the nearest hundredL
Round 168 to the nearest tenE
Round 286 to the nearest tenU
Round 131 to the nearest tenM
Round 48 to the nearest tenR
Round 1,141 to the nearest hundredD
Round 4,311 to the nearest hundredA
Round 94 to the nearest tenH
Round 428 to the nearest tenN
Round 233 to the nearest tenG
Round 3,702 to the nearest hundredV
Round 1,663 to the nearest hundredP
Round 7,448 to the nearest thousandO
Round 2,884 to the nearest hundredI
Round 3,359 to the nearest thousandS
0/16 letters found
Clue 2
Addition
Mechanic Meg counted all the spare gears from both storage bins. Add them up to find where the suspect went.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
A
8261
2167
2204
4599
4978
9176
2723
2723
2723
A
8261
2167
A
8261
9551
9176
4978
4599
9770
2204
6314
4434
4599
A
8261
4978
4599
9176
4978
4978
A
8261
3274 + 4987 =A
1218 + 986 =I
2623 + 2355 =N
2693 + 1741 =H
1227 + 940 =W
1557 + 1166 =S
2959 + 1640 =T
5278 + 3898 =E
3448 + 2866 =G
3413 + 6357 =R
5037 + 4514 =B
0/11 letters found
Clue 3
Subtraction
The main battery drained when the culprit scrambled the server. Subtract the lost charge to trace the signal.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
T
3319
2729
6661
5168
3386
8297
8297
2955
3551
2018
5168
5168
T
3319
8297
2955
2955
6661
8416
3304
4056
3479
2018
1007
3386
6661
T
3319
T
3319
8587
2018
2955
5168
6950 - 3631 =T
6383 - 2327 =Y
4197 - 3190 =G
4249 - 1294 =P
4856 - 2127 =H
8176 - 4790 =N
7494 - 4190 =B
4725 - 1174 =W
7366 - 3887 =M
11815 - 3518 =O
5157 - 3139 =A
8750 - 3582 =S
9950 - 1363 =R
11963 - 3547 =D
11267 - 4606 =E
0/15 letters found
Clue 4
Multiplication facts (1-12)
The factory floor has equal rows of charging pods. Multiply the rows and pods to locate the hidden wire.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
S
8
99
1
27
54
49
100
36
49
30
27
42
S
8
S
8
40
48
55
88
49
48
88
18
1
49
49
88
55
110
1
49
S
8
2 × 4 =S
8 × 11 =N
4 × 10 =H
3 × 6 =G
11 × 5 =W
3 × 9 =A
6 × 7 =L
10 × 10 =D
1 × 1 =R
7 × 7 =E
11 × 9 =C
8 × 6 =O
6 × 9 =P
11 × 10 =I
9 × 4 =M
3 × 10 =T
0/16 letters found
Clue 5
Division facts (1-12) — the last clue
The repair bots must share the oil canisters equally. Divide the batch to get the final passcode.
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
25 ÷ 5 = ?
60 ÷ 5 = ?
4 ÷ 2 = ?
63 ÷ 9 = ?
11 ÷ 11 = ?
12 ÷ 4 = ?
110 ÷ 10 = ?
42 ÷ 7 = ?
40 ÷ 10 = ?
120 ÷ 12 = ?
9 ÷ 1 = ?
Step 2 — cross out the sentence with each answer
1.The villain zapped a plasma spark, then zoomed up on rocket boots.
2.The villain blasted a frost beam, then flew away with hover jets.
3.The villain fired a laser torch, then swung off with a grapple arm.
4.The villain blasted a frost beam, then zipped off on turbo treads.
5.The villain fired a laser torch, then vanished in a stealth cloak.
6.The villain pulsed a magnet beam, then vanished in a stealth cloak.
7.The villain pulsed a magnet beam, then swung off with a grapple arm.
8.The villain fired a laser torch, then flew away with hover jets.
9.The villain blasted a frost beam, then zoomed up on rocket boots.
10.The villain emitted a sonic hum, then swung off with a grapple arm.
11.The villain zapped a plasma spark, then flew away with hover jets.
12.The villain emitted a sonic hum, then flew away with hover jets.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Great Cog Caper
Culprit: Unit A1 (laser torch · hover jets · right antenna bent · neon green wires · magnet traps)
- Clue 1 (Rounding): "THE VILLAIN DOES NOT USE A GRAPPLE ARM"Round 24 to the nearest ten = 20 (T) · Round 152 to the nearest hundred = 200 (L) · Round 168 to the nearest ten = 170 (E) · Round 286 to the nearest ten = 290 (U) · Round 131 to the nearest ten = 130 (M) · Round 48 to the nearest ten = 50 (R) · Round 1,141 to the nearest hundred = 1100 (D) · Round 4,311 to the nearest hundred = 4300 (A) · Round 94 to the nearest ten = 90 (H) · Round 428 to the nearest ten = 430 (N) · Round 233 to the nearest ten = 230 (G) · Round 3,702 to the nearest hundred = 3700 (V) · Round 1,663 to the nearest hundred = 1700 (P) · Round 7,448 to the nearest thousand = 7000 (O) · Round 2,884 to the nearest hundred = 2900 (I) · Round 3,359 to the nearest thousand = 3000 (S)
- Clue 2 (Addition): "A WITNESS SAW A BENT RIGHT ANTENNA"3274 + 4987 = 8261 (A) · 1218 + 986 = 2204 (I) · 2623 + 2355 = 4978 (N) · 2693 + 1741 = 4434 (H) · 1227 + 940 = 2167 (W) · 1557 + 1166 = 2723 (S) · 2959 + 1640 = 4599 (T) · 5278 + 3898 = 9176 (E) · 3448 + 2866 = 6314 (G) · 3413 + 6357 = 9770 (R) · 5037 + 4514 = 9551 (B)
- Clue 3 (Subtraction): "THE SNOOP WAS STOPPED BY MAGNET TRAPS"6950 - 3631 = 3319 (T) · 6383 - 2327 = 4056 (Y) · 4197 - 3190 = 1007 (G) · 4249 - 1294 = 2955 (P) · 4856 - 2127 = 2729 (H) · 8176 - 4790 = 3386 (N) · 7494 - 4190 = 3304 (B) · 4725 - 1174 = 3551 (W) · 7366 - 3887 = 3479 (M) · 11815 - 3518 = 8297 (O) · 5157 - 3139 = 2018 (A) · 8750 - 3582 = 5168 (S) · 9950 - 1363 = 8587 (R) · 11963 - 3547 = 8416 (D) · 11267 - 4606 = 6661 (E)
- Clue 4 (Multiplication facts (1-12)): "SCRAPED METALS SHOW NEON GREEN WIRES"2 × 4 = 8 (S) · 8 × 11 = 88 (N) · 4 × 10 = 40 (H) · 3 × 6 = 18 (G) · 11 × 5 = 55 (W) · 3 × 9 = 27 (A) · 6 × 7 = 42 (L) · 10 × 10 = 100 (D) · 1 × 1 = 1 (R) · 7 × 7 = 49 (E) · 11 × 9 = 99 (C) · 8 × 6 = 48 (O) · 6 × 9 = 54 (P) · 11 × 10 = 110 (I) · 9 × 4 = 36 (M) · 3 × 10 = 30 (T)
- Clue 5 (Division facts (1-12)): surviving statement (box 8) → Unit A125 ÷ 5 = 5 · 60 ÷ 5 = 12 · 4 ÷ 2 = 2 · 63 ÷ 9 = 7 · 11 ÷ 11 = 1 · 12 ÷ 4 = 3 · 110 ÷ 10 = 11 · 42 ÷ 7 = 6 · 40 ÷ 10 = 4 · 120 ÷ 12 = 10 · 9 ÷ 1 = 9
About this mystery
- Grade level
- Grade 4 math
- Math topics
- Rounding, Addition, Subtraction, Multiplication, Division
- Reading level
- grades 3-4
- Theme
- The Great Cog Caper — set in The Rust City Robotics Lab
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects