🌊 OceanGrade 8Reading: grades 7-9ExponentsSquare rootsPythagorean theoremOrder of operationsTwo-step equations
The Sub-Oceanic Heist
An alarm echoes through the metallic halls of Outpost Lambda. Someone has breached the deep-sea vault and stolen the Poseidon Core! As the leading marine detective, you must analyze the sonar logs and gear signatures before the thief escapes into the black abyss.
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 Gear | Auxiliary Tool | Dive Watch Wrist | Wetsuit Hood | Siren Song Freq |
|---|---|---|---|---|---|
| Jeanne Baret | Heavy Harpoon | Flashlight | Left Wrist Watch | Kelp Green | Low Hum |
| Matthew Maury | Seismic Probe | Flashlight | Right Wrist Watch | Sandy Blonde | Deep Bass |
| Edward Forbes | Hydro-Thruster | Coral Hook | Left Wrist Watch | Kelp Green | Deep Bass |
| Mary Anning | Plasma Cutter | Scanner | Left Wrist Watch | Kelp Green | High Pitch |
| Marie Tharp | Heavy Harpoon | Flashlight | Right Wrist Watch | Kelp Green | High Pitch |
| Alistair Hardy | Plasma Cutter | Laser Pointer | Left Wrist Watch | Kelp Green | High Pitch |
| Henry Bryant | Plasma Cutter | Coral Hook | Right Wrist Watch | Deep Navy | Deep Bass |
| Charles Darwin | Triton Net | Coral Hook | Left Wrist Watch | Sandy Blonde | Deep Bass |
| Jacques Cousteau | Plasma Cutter | Laser Pointer | Left Wrist Watch | Kelp Green | Deep Bass |
| David Attenborough | Hydro-Thruster | Laser Pointer | Right Wrist Watch | Kelp Green | Deep Bass |
| Vagn Ekman | Plasma Cutter | Scanner | Left Wrist Watch | Deep Navy | Low Hum |
| Hans Hass | Heavy Harpoon | Sonar Flare | Left Wrist Watch | Kelp Green | Deep Bass |
| Eugenie Clark | Plasma Cutter | Coral Hook | Right Wrist Watch | Deep Navy | High Pitch |
| Walter Munk | Plasma Cutter | Flashlight | Left Wrist Watch | Kelp Green | Deep Bass |
| Sylvia Earle | Heavy Harpoon | Sonar Flare | Left Wrist Watch | Sandy Blonde | High Pitch |
| Nancy Foster | Heavy Harpoon | Flashlight | Left Wrist Watch | Kelp Green | Deep Bass |
| Cindy Lee Van | Seismic Probe | Scanner | Left Wrist Watch | Sandy Blonde | Deep Bass |
| Ernest Shackleton | Seismic Probe | Scanner | Right Wrist Watch | Deep Navy | High Pitch |
| Robert Ballard | Triton Net | Sonar Flare | Right Wrist Watch | Deep Navy | Low Hum |
| James Cameron | Hydro-Thruster | Scanner | Left Wrist Watch | Deep Navy | High Pitch |
| Rachel Carson | Hydro-Thruster | Sonar Flare | Left Wrist Watch | Kelp Green | Low Hum |
Clue 1
Exponents
The deep-sea pressure sensors recorded an exponential energy spike in the water. By calculating the power of the base reading, we can determine 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
441
484
36
256
125
256
81
36
400
T
441
64
343
36
256
121
343
T
441
125
256
36
128
256
343
121
128
27
512
225
128
27
36
21^2 =T
2^6 =D
3^3 =R
16^2 =S
20^2 =C
2^9 =F
3^4 =P
5^3 =U
15^2 =L
7^3 =O
22^2 =H
2^7 =A
11^2 =N
6^2 =E
0/14 letters found
Clue 2
Square roots
We mapped the square grid of the flooded ruins where the thief escaped. Solving for the square root of the total area will reveal the suspect's watch preference.
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
24
2
18
17
5
23
17
18
16
5
12
12
18
4
23
20
18
7
21
11
T
24
2
18
13
18
8
T
24
16
20
6
12
T
24
sqrt(576) =T
sqrt(36) =I
sqrt(529) =U
sqrt(49) =D
sqrt(25) =A
sqrt(400) =R
sqrt(324) =E
sqrt(64) =F
sqrt(256) =W
sqrt(289) =G
sqrt(441) =O
sqrt(169) =L
sqrt(144) =S
sqrt(121) =N
sqrt(4) =H
sqrt(16) =C
0/16 letters found
Clue 3
Pythagorean theorem
Our submarine chased the thief along a diagonal path across the trench. Finding the hypotenuse of our dive path gives us the exact frequency needed to stop them.
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
37
5
13
40
10
58
58
26
10
34
51
5
30
26
34
39
82
30
87
17
26
15
13
13
52
29
26
51
51
legs 12 and 35, hypotenuse =T
legs 15 and 36, hypotenuse =K
legs 18 and 24, hypotenuse =R
legs 40 and 42, hypotenuse =L
legs 20 and 21, hypotenuse =B
legs 24 and 32, hypotenuse =V
legs 8 and 15, hypotenuse =M
legs 5 and 12, hypotenuse =E
legs 16 and 30, hypotenuse =N
legs 3 and 4, hypotenuse =H
legs 60 and 63, hypotenuse =O
legs 10 and 24, hypotenuse =A
legs 24 and 45, hypotenuse =S
legs 20 and 48, hypotenuse =P
legs 6 and 8, hypotenuse =I
legs 18 and 80, hypotenuse =F
legs 9 and 12, hypotenuse =D
0/17 letters found
Clue 4
Order of operations
A damaged underwater tablet contains encrypted gear logs. By following the correct order of operations, we can decode the wetsuit hood color left behind.
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
27
62
94
48
55
89
26
94
94
9
33
38
26
A
27
9
88
80
A
27
33
85
9
38
77
94
41
A
27
48
41
94
9 × 5 - 18 =A
11 × 10 - 22 =D
6 × 9 - 16 =T
12 × 10 - 26 =E
26 + 9 × 4 =K
9 × 8 - 24 =L
10 × 11 - 21 =G
9 × 3 - 18 =N
5 + 7 × 3 =R
38 + 6 × 7 =W
11 × 6 - 25 =V
11 × 5 - 22 =S
10 × 10 - 15 =I
11 × 8 - 11 =H
40 + 3 × 5 =P
0/15 letters found
Clue 5
Two-step equations — the last clue
We need to calculate how fast the thief's mini-sub is draining its battery over time. Solving this two-step equation isolates the thief's identity.
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
4x + 6 = 30, x = ?
3x + 9 = 30, x = ?
6x + 4 = 10, x = ?
3x + 6 = 33, x = ?
5x + 3 = 58, x = ?
4x + 12 = 20, x = ?
4x + 12 = 52, x = ?
5x + 6 = 26, x = ?
4x + 11 = 23, x = ?
6x + 3 = 33, x = ?
4x + 12 = 44, x = ?
Step 2 — cross out the sentence with each answer
1.The villain ignited a plasma cutter to slice the hatch, then blinded the security cameras with a flashlight.
2.The villain fired a heavy harpoon to crack the vault, then detonated a sonar flare to scramble the radar.
3.The villain fired a heavy harpoon to crack the vault, then snagged the ancient pearl using a coral hook.
4.The villain planted a seismic probe near the foundation, then snagged the ancient pearl using a coral hook.
5.The villain ignited a plasma cutter to slice the hatch, then hacked the ocean lab console with a scanner.
6.The villain ignited a plasma cutter to slice the hatch, then swept the dark waters with a laser pointer.
7.The villain fired a heavy harpoon to crack the vault, then blinded the security cameras with a flashlight.
8.The villain cast a triton net to trap the reef guardian, then swept the dark waters with a laser pointer.
9.The villain cast a triton net to trap the reef guardian, then blinded the security cameras with a flashlight.
10.The villain planted a seismic probe near the foundation, then detonated a sonar flare to scramble the radar.
11.The villain revved a hydro-thruster to blast the gate, then swept the dark waters with a laser pointer.
12.The villain revved a hydro-thruster to blast the gate, then snagged the ancient pearl using a coral hook.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Sub-Oceanic Heist
Culprit: Edward Forbes (Hydro-Thruster · Coral Hook · Left Wrist Watch · Kelp Green · Deep Bass)
- Clue 1 (Exponents): "THE SUSPECT DOES NOT USE A SONAR FLARE"21^2 = 441 (T) · 2^6 = 64 (D) · 3^3 = 27 (R) · 16^2 = 256 (S) · 20^2 = 400 (C) · 2^9 = 512 (F) · 3^4 = 81 (P) · 5^3 = 125 (U) · 15^2 = 225 (L) · 7^3 = 343 (O) · 22^2 = 484 (H) · 2^7 = 128 (A) · 11^2 = 121 (N) · 6^2 = 36 (E)
- Clue 2 (Square roots): "THE GAUGE WAS SECURED ON THE LEFT WRIST"sqrt(576) = 24 (T) · sqrt(36) = 6 (I) · sqrt(529) = 23 (U) · sqrt(49) = 7 (D) · sqrt(25) = 5 (A) · sqrt(400) = 20 (R) · sqrt(324) = 18 (E) · sqrt(64) = 8 (F) · sqrt(256) = 16 (W) · sqrt(289) = 17 (G) · sqrt(441) = 21 (O) · sqrt(169) = 13 (L) · sqrt(144) = 12 (S) · sqrt(121) = 11 (N) · sqrt(4) = 2 (H) · sqrt(16) = 4 (C)
- Clue 3 (Pythagorean theorem): "THE VILLAIN SHRANK FROM A DEEP BASS"legs 12 and 35, hypotenuse = 37 (T) · legs 15 and 36, hypotenuse = 39 (K) · legs 18 and 24, hypotenuse = 30 (R) · legs 40 and 42, hypotenuse = 58 (L) · legs 20 and 21, hypotenuse = 29 (B) · legs 24 and 32, hypotenuse = 40 (V) · legs 8 and 15, hypotenuse = 17 (M) · legs 5 and 12, hypotenuse = 13 (E) · legs 16 and 30, hypotenuse = 34 (N) · legs 3 and 4, hypotenuse = 5 (H) · legs 60 and 63, hypotenuse = 87 (O) · legs 10 and 24, hypotenuse = 26 (A) · legs 24 and 45, hypotenuse = 51 (S) · legs 20 and 48, hypotenuse = 52 (P) · legs 6 and 8, hypotenuse = 10 (I) · legs 18 and 80, hypotenuse = 82 (F) · legs 9 and 12, hypotenuse = 15 (D)
- Clue 4 (Order of operations): "A KELP GREEN STRAND WAS IN THE VALVE"9 × 5 - 18 = 27 (A) · 11 × 10 - 22 = 88 (D) · 6 × 9 - 16 = 38 (T) · 12 × 10 - 26 = 94 (E) · 26 + 9 × 4 = 62 (K) · 9 × 8 - 24 = 48 (L) · 10 × 11 - 21 = 89 (G) · 9 × 3 - 18 = 9 (N) · 5 + 7 × 3 = 26 (R) · 38 + 6 × 7 = 80 (W) · 11 × 6 - 25 = 41 (V) · 11 × 5 - 22 = 33 (S) · 10 × 10 - 15 = 85 (I) · 11 × 8 - 11 = 77 (H) · 40 + 3 × 5 = 55 (P)
- Clue 5 (Two-step equations): surviving statement (box 12) → Edward Forbes4x + 6 = 30, x = 6 · 3x + 9 = 30, x = 7 · 6x + 4 = 10, x = 1 · 3x + 6 = 33, x = 9 · 5x + 3 = 58, x = 11 · 4x + 12 = 20, x = 2 · 4x + 12 = 52, x = 10 · 5x + 6 = 26, x = 4 · 4x + 11 = 23, x = 3 · 6x + 3 = 33, x = 5 · 4x + 12 = 44, x = 8
About this mystery
- Grade level
- Grade 8 math
- Math topics
- Exponents, Square roots, Pythagorean theorem, Order of operations, Two-step equations
- Reading level
- grades 7-9
- Theme
- The Sub-Oceanic Heist — set in Abyssal Trench Outpost Lambda
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects