🤖 RobotsGrade 3Reading: grades 3-4Place valueAdditionMultiplicationSubtractionDivision
The Case of the Missing Mega-Core
Someone broke into the central power plant and took the Golden Mega-Core! Robo-City will lose power unless we find the Rogue Robot who did it.
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 Tool | Backup Gadget | LED Scan Direction | Antenna Light | System Vulnerability |
|---|---|---|---|---|---|
| Wallie | Magnet Arm | Hologram Projector | Vertical Blink | Neon Green Glow | Strong Magnets |
| Optimus | Magnet Arm | Grappling Hook | Horizontal Sweep | Bright Yellow Spark | Water Splashes |
| Clank | Laser Welder | Hologram Projector | Horizontal Sweep | Neon Green Glow | Static Electricity |
| Vector | Laser Welder | Hologram Projector | Vertical Blink | Neon Green Glow | Static Electricity |
| Geary | Rocket Thruster | Grappling Hook | Horizontal Sweep | Neon Green Glow | Static Electricity |
| Widget | Plasma Cutter | Force Field | Vertical Blink | Neon Green Glow | Static Electricity |
| Copper | Sonic Drill | Radar Scanner | Vertical Blink | Neon Green Glow | Static Electricity |
| Zippy | Plasma Cutter | Smoke Screen | Vertical Blink | Neon Green Glow | Static Electricity |
| Data | Magnet Arm | Force Field | Vertical Blink | Bright Yellow Spark | Static Electricity |
| Sprocket | Plasma Cutter | Hologram Projector | Vertical Blink | Neon Green Glow | Strong Magnets |
| Albie | Plasma Cutter | Grappling Hook | Vertical Blink | Neon Green Glow | Water Splashes |
| Tinny | Sonic Drill | Smoke Screen | Horizontal Sweep | Bright Yellow Spark | Strong Magnets |
| Buster | Laser Welder | Radar Scanner | Vertical Blink | Neon Green Glow | Water Splashes |
| Bender | Laser Welder | Grappling Hook | Vertical Blink | Bright Yellow Spark | Static Electricity |
| Beep | Rocket Thruster | Force Field | Vertical Blink | Bright Yellow Spark | Strong Magnets |
| Gizmo | Laser Welder | Grappling Hook | Vertical Blink | Neon Green Glow | Water Splashes |
| Eve | Plasma Cutter | Grappling Hook | Horizontal Sweep | Ruby Red Flash | Strong Magnets |
| Rusty | Magnet Arm | Grappling Hook | Vertical Blink | Neon Green Glow | Static Electricity |
| Circuit | Sonic Drill | Grappling Hook | Horizontal Sweep | Neon Green Glow | Static Electricity |
| Sparky | Sonic Drill | Hologram Projector | Vertical Blink | Bright Yellow Spark | Static Electricity |
| Megatron | Plasma Cutter | Force Field | Vertical Blink | Ruby Red Flash | Strong Magnets |
Clue 1
Place value
We plug the broken decoder chip into our computer. To read the first file, we must find the digit in the hundreds place of the chip's serial code.
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
30
300
60
4000
100
5000
5000
900
100
700
1000
400
60
20
700
400
T
30
9000
20
60
900
600
400
70
500
60
600
100
60
5000
1000
What is the value of the 3 in 639?T
What is the value of the 2 in 126?S
What is the value of the 3 in 1,309?H
What is the value of the 5 in 3,538?C
What is the value of the 9 in 69,183?U
What is the value of the 7 in 174?R
What is the value of the 6 in 4,160?E
What is the value of the 7 in 791?N
What is the value of the 1 in 1,563?D
What is the value of the 6 in 681?F
What is the value of the 1 in 7,147?I
What is the value of the 9 in 928?A
What is the value of the 4 in 475?O
What is the value of the 4 in 84,519?V
What is the value of the 5 in 65,336?L
0/15 letters found
Clue 2
Addition
To open the security locker, we need to add the total number of spare gears found on the workbench and type the sum into the keypad.
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
344
499
944
308
835
973
374
T
344
507
728
397
635
397
T
344
635
374
689
442
555
319
689
T
344
319
374
944
279
578
944
728
T
344
689
342
835
374
374
507
169 + 175 =T
192 + 116 =F
174 + 404 =V
151 + 128 =D
584 + 251 =A
473 + 255 =R
245 + 254 =H
257 + 117 =L
339 + 634 =U
244 + 153 =O
275 + 280 =K
138 + 204 =C
464 + 225 =I
299 + 143 =N
472 + 472 =E
191 + 316 =Y
388 + 247 =B
115 + 204 =S
0/18 letters found
Clue 3
Multiplication facts (1-12)
The warehouse floor has rows of storage crates. By multiplying the rows of crates by the boxes in each row, we find the secret room code.
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
96
6
56
6
35
64
90
108
90
64
6
44
35
64
35
6
81
80
56
45
S
96
6
10
90
4
35
108
108
56
35
48
S
96
3
90
56
44
S
96
8 × 12 =S
1 × 3 =G
9 × 9 =Y
1 × 10 =H
9 × 5 =M
7 × 5 =I
12 × 9 =L
4 × 1 =V
9 × 10 =E
6 × 1 =T
7 × 8 =A
11 × 4 =R
8 × 10 =J
8 × 8 =C
8 × 6 =N
0/15 letters found
Clue 4
Subtraction
We need to override the energy grid. We subtract the drained battery packs from the fully charged ones to find how many power units are left.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
W
202
430
196
163
803
738
663
738
430
163
738
477
463
430
430
738
477
670
163
W
202
397
289
463
797
331
289
199
199
760
430
331
518
430
738
430
227 - 25 =W
473 - 10 =R
446 - 250 =F
915 - 397 =C
630 - 299 =S
908 - 111 =K
567 - 278 =A
960 - 157 =U
1036 - 366 =L
608 - 211 =M
817 - 154 =D
565 - 135 =E
461 - 298 =O
319 - 120 =T
773 - 13 =H
581 - 104 =G
1102 - 364 =N
0/17 letters found
Clue 5
Division facts (1-12) — the last clue
We must share the emergency oil canisters equally among the helper bots. Dividing the cans tells us the final number we need to open the safe.
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
18 ÷ 3 = ?
30 ÷ 3 = ?
22 ÷ 11 = ?
7 ÷ 7 = ?
54 ÷ 6 = ?
6 ÷ 2 = ?
77 ÷ 11 = ?
25 ÷ 5 = ?
48 ÷ 4 = ?
132 ÷ 12 = ?
72 ÷ 9 = ?
Step 2 — cross out the sentence with each answer
1.The villain melts the security locks into liquid metal, then blocks the laser darts with an energy shield.
2.The villain slices through the heavy steel vault gate, then confuses the guards with duplicate images.
3.The villain drills a massive hole through the concrete floor, then confuses the guards with duplicate images.
4.The villain drills a massive hole through the concrete floor, then tracks the cleanest escape path through the vents.
5.The villain slices through the heavy steel vault gate, then escapes into a cloud of thick gray mist.
6.The villain yanks the metal power box off the wall, then swings away using a long steel cable.
7.The villain drills a massive hole through the concrete floor, then swings away using a long steel cable.
8.The villain drills a massive hole through the concrete floor, then blocks the laser darts with an energy shield.
9.The villain melts the security locks into liquid metal, then confuses the guards with duplicate images.
10.The villain melts the security locks into liquid metal, then escapes into a cloud of thick gray mist.
11.The villain blasts into the sky with a loud roar, then tracks the cleanest escape path through the vents.
12.The villain melts the security locks into liquid metal, then swings away using a long steel cable.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Case of the Missing Mega-Core
Culprit: Copper (Sonic Drill · Radar Scanner · Vertical Blink · Neon Green Glow · Static Electricity)
- Clue 1 (Place value): "THE VILLAIN DOES NOT USE A FORCE FIELD"What is the value of the 3 in 639? = 30 (T) · What is the value of the 2 in 126? = 20 (S) · What is the value of the 3 in 1,309? = 300 (H) · What is the value of the 5 in 3,538? = 500 (C) · What is the value of the 9 in 69,183? = 9000 (U) · What is the value of the 7 in 174? = 70 (R) · What is the value of the 6 in 4,160? = 60 (E) · What is the value of the 7 in 791? = 700 (N) · What is the value of the 1 in 1,563? = 1000 (D) · What is the value of the 6 in 681? = 600 (F) · What is the value of the 1 in 7,147? = 100 (I) · What is the value of the 9 in 928? = 900 (A) · What is the value of the 4 in 475? = 400 (O) · What is the value of the 4 in 84,519? = 4000 (V) · What is the value of the 5 in 65,336? = 5000 (L)
- Clue 2 (Addition): "THE FAULTY ROBOT BLINKS ITS LED VERTICALLY"169 + 175 = 344 (T) · 192 + 116 = 308 (F) · 174 + 404 = 578 (V) · 151 + 128 = 279 (D) · 584 + 251 = 835 (A) · 473 + 255 = 728 (R) · 245 + 254 = 499 (H) · 257 + 117 = 374 (L) · 339 + 634 = 973 (U) · 244 + 153 = 397 (O) · 275 + 280 = 555 (K) · 138 + 204 = 342 (C) · 464 + 225 = 689 (I) · 299 + 143 = 442 (N) · 472 + 472 = 944 (E) · 191 + 316 = 507 (Y) · 388 + 247 = 635 (B) · 115 + 204 = 319 (S)
- Clue 3 (Multiplication facts (1-12)): "STATIC ELECTRICITY JAMS THE VILLAINS GEARS"8 × 12 = 96 (S) · 1 × 3 = 3 (G) · 9 × 9 = 81 (Y) · 1 × 10 = 10 (H) · 9 × 5 = 45 (M) · 7 × 5 = 35 (I) · 12 × 9 = 108 (L) · 4 × 1 = 4 (V) · 9 × 10 = 90 (E) · 6 × 1 = 6 (T) · 7 × 8 = 56 (A) · 11 × 4 = 44 (R) · 8 × 10 = 80 (J) · 8 × 8 = 64 (C) · 8 × 6 = 48 (N)
- Clue 4 (Subtraction): "WE FOUND NEON GREEN GLOW MARKS AT THE SCENE"227 - 25 = 202 (W) · 473 - 10 = 463 (R) · 446 - 250 = 196 (F) · 915 - 397 = 518 (C) · 630 - 299 = 331 (S) · 908 - 111 = 797 (K) · 567 - 278 = 289 (A) · 960 - 157 = 803 (U) · 1036 - 366 = 670 (L) · 608 - 211 = 397 (M) · 817 - 154 = 663 (D) · 565 - 135 = 430 (E) · 461 - 298 = 163 (O) · 319 - 120 = 199 (T) · 773 - 13 = 760 (H) · 581 - 104 = 477 (G) · 1102 - 364 = 738 (N)
- Clue 5 (Division facts (1-12)): surviving statement (box 4) → Copper18 ÷ 3 = 6 · 30 ÷ 3 = 10 · 22 ÷ 11 = 2 · 7 ÷ 7 = 1 · 54 ÷ 6 = 9 · 6 ÷ 2 = 3 · 77 ÷ 11 = 7 · 25 ÷ 5 = 5 · 48 ÷ 4 = 12 · 132 ÷ 12 = 11 · 72 ÷ 9 = 8
About this mystery
- Grade level
- Grade 3 math
- Math topics
- Place value, Addition, Multiplication, Subtraction, Division
- Reading level
- grades 3-4
- Theme
- The Case of the Missing Mega-Core — set in The Robo-City Scrap Yards
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects