🏴☠️ Pirates, MermaidsGrade 7Reading: grades 7-9Place valueAdditionSubtractionMultiplicationMissing addends
The Mystery of Siren Cove
A rogue captain has raided the sacred vaults of Siren Cove, stealing ancient magical relics and disrupting the delicate truce between pirates and merfolk. As the chief investigator, you must use marine logs, wreckage evidence, and mathematical clues to track down the culprit before they escape across the ocean.
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 | Seafaring Skill | Stolen Relic | Dominant Hand | Hair Color | Vulnerability |
|---|---|---|---|---|---|
| Calico Jack | Tide Control | Enchanted Spyglass | Left Handed | Seaweed Green | Pure Iron |
| Thomas Tew | Compass Bending | Golden Compass | Right Handed | Seaweed Green | Pure Iron |
| Grace OMalley | Cannon Blasting | Pearl Shield | Left Handed | Seaweed Green | Pure Iron |
| Jacquotte Delahaye | Compass Bending | Pearl Shield | Right Handed | Seaweed Green | Pure Iron |
| Anne Bonny | Compass Bending | Golden Compass | Right Handed | Seaweed Green | Sunken Gold |
| Henry Morgan | Ship Sinking | Obsidian Cutlass | Left Handed | Seaweed Green | Pure Iron |
| Sayyida al Hurra | Ship Sinking | Pearl Shield | Right Handed | Coral Red | Fresh Water |
| Blackbeard | Cannon Blasting | Enchanted Spyglass | Right Handed | Midnight Black | Sunken Gold |
| Stede Bonnet | Tide Control | Obsidian Cutlass | Right Handed | Midnight Black | Fresh Water |
| Francis Drake | Tide Control | Golden Compass | Left Handed | Coral Red | Pure Iron |
| Zheng Yi Sao | Siren Song | Enchanted Spyglass | Right Handed | Midnight Black | Pure Iron |
| Charles Vane | Compass Bending | Pearl Shield | Right Handed | Seaweed Green | Fresh Water |
| Woodes Rogers | Cannon Blasting | Trident of Tides | Left Handed | Seaweed Green | Fresh Water |
| William Kidd | Tide Control | Pearl Shield | Right Handed | Seaweed Green | Fresh Water |
| Francois lOlonnais | Cannon Blasting | Golden Compass | Left Handed | Seaweed Green | Pure Iron |
| Mary Read | Siren Song | Trident of Tides | Right Handed | Coral Red | Pure Iron |
| Jean Lafitte | Cannon Blasting | Enchanted Spyglass | Right Handed | Coral Red | Pure Iron |
| Howell Davis | Compass Bending | Enchanted Spyglass | Left Handed | Seaweed Green | Sunken Gold |
| Charlotte de Berry | Siren Song | Trident of Tides | Left Handed | Coral Red | Sunken Gold |
| Edward Low | Siren Song | Trident of Tides | Left Handed | Seaweed Green | Pure Iron |
| Samuel Bellamy | Ship Sinking | Enchanted Spyglass | Right Handed | Midnight Black | Pure Iron |
Clue 1
Place value
The sea captain examines a coded logbook where digit positions reveal a secret naval coordinate.
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
600
400
200
50
2000
70
8000
7000
700
T
600
300
500
200
3000
9000
500
T
600
2000
3000
200
800
9000
500
5000
3000
700
300
700
800
9000
50
2000
T
600
70
800
3000
3000
What is the value of the 6 in 52,631?T
What is the value of the 5 in 115,368?B
What is the value of the 3 in 543,464?S
What is the value of the 4 in 69,419?H
What is the value of the 7 in 114,761?I
What is the value of the 3 in 744,300?D
What is the value of the 7 in 14,873?L
What is the value of the 8 in 258,266?P
What is the value of the 8 in 922,806?A
What is the value of the 2 in 62,097?U
What is the value of the 2 in 69,276?E
What is the value of the 7 in 207,804?R
What is the value of the 5 in 27,547?O
What is the value of the 9 in 569,403?N
What is the value of the 5 in 68,050?C
0/15 letters found
Clue 2
Addition
The crew tallies up recovered barrels of gunpowder from two captured galleons to measure their total supplies.
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
6704
4278
3390
8706
3296
3704
A
6704
2853
7542
3390
7542
3480
4515
7360
2853
3296
8615
A
6704
2576
4278
3390
8706
3296
4663
2853
3296
3704
3390
8731
A
6704
3480
3296
7360
3593
3390
2576
3704
7360
3480
2282 + 4422 =A
1629 + 2075 =H
1988 + 2290 =L
1284 + 2309 =V
4889 + 3842 =C
995 + 2301 =T
2011 + 2504 =R
2314 + 5228 =D
4228 + 4387 =W
2790 + 4570 =I
4344 + 4362 =F
1712 + 1141 =N
1830 + 2833 =O
907 + 1669 =S
1684 + 1706 =E
2287 + 1193 =P
0/16 letters found
Clue 3
Subtraction
The navigator calculates how many nautical miles remain after dodging a sudden sea monster.
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
1844
4352
8660
2565
8243
5439
7560
3335
2758
6678
8660
5589
3834
5589
2815
3335
8243
4352
8660
2758
8985
T
1844
8985
2565
1561
5439
6678
2758
5439
3834
1988
7560
6678
8660
2815
6678
5439
3335
5794 - 3950 =T
8299 - 2710 =L
10088 - 1428 =E
4005 - 1247 =D
2809 - 1248 =W
8904 - 661 =C
4305 - 970 =N
11232 - 4554 =R
9562 - 577 =A
3643 - 828 =I
7786 - 2347 =O
4722 - 370 =H
5809 - 3821 =P
4484 - 650 =F
2752 - 187 =S
12087 - 4527 =U
0/16 letters found
Clue 4
Multiplication facts (1-12)
The quartermaster counts identical crates of ship supplies stacked in equal rows along the lower deck.
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
108
90
77
35
33
32
S
108
2
44
S
108
14
35
120
14
14
32
60
77
14
14
33
66
35
70
77
8
35
12
60
66
90
2
33
90
35
8
99
18
14
12 × 9 =S
12 × 10 =W
5 × 7 =A
11 × 4 =F
7 × 10 =I
2 × 6 =U
7 × 11 =R
10 × 9 =T
12 × 5 =G
2 × 1 =O
6 × 3 =L
11 × 6 =H
11 × 9 =K
4 × 2 =C
8 × 4 =D
7 × 2 =E
11 × 3 =N
0/17 letters found
Clue 5
Missing addends — the last clue
The lookout compares the weight of plunder on the scale with the missing cargo to solve the shortfall.
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
7 + ___ = 8
7 + ___ = 17
39 + ___ = 43
23 + ___ = 26
8 + ___ = 14
38 + ___ = 46
15 + ___ = 24
20 + ___ = 25
7 + ___ = 18
16 + ___ = 23
20 + ___ = 32
Step 2 — cross out the sentence with each answer
1.The villain sang a hypnotic siren song, then stole the Trident of Tides.
2.The villain summoned rogue tidal waves, then took the Enchanted Spyglass.
3.The villain bent the ships compasses, then stole the Trident of Tides.
4.The villain blasted the starboard cannons, then stole the Pearl Shield.
5.The villain summoned rogue tidal waves, then claimed the Obsidian Cutlass.
6.The villain bent the ships compasses, then stole the Pearl Shield.
7.The villain sang a hypnotic siren song, then claimed the Obsidian Cutlass.
8.The villain blasted the starboard cannons, then stole the Trident of Tides.
9.The villain blasted the starboard cannons, then took the Enchanted Spyglass.
10.The villain blasted the starboard cannons, then snatched the Golden Compass.
11.The villain bent the ships compasses, then claimed the Obsidian Cutlass.
12.The villain sang a hypnotic siren song, then took the Enchanted Spyglass.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Mystery of Siren Cove
Culprit: Calico Jack (Tide Control · Enchanted Spyglass · Left Handed · Seaweed Green · Pure Iron)
- Clue 1 (Place value): "THE CULPRIT DOES NOT USE AN OBSIDIAN CUTLASS"What is the value of the 6 in 52,631? = 600 (T) · What is the value of the 5 in 115,368? = 5000 (B) · What is the value of the 3 in 543,464? = 3000 (S) · What is the value of the 4 in 69,419? = 400 (H) · What is the value of the 7 in 114,761? = 700 (I) · What is the value of the 3 in 744,300? = 300 (D) · What is the value of the 7 in 14,873? = 70 (L) · What is the value of the 8 in 258,266? = 8000 (P) · What is the value of the 8 in 922,806? = 800 (A) · What is the value of the 2 in 62,097? = 2000 (U) · What is the value of the 2 in 69,276? = 200 (E) · What is the value of the 7 in 207,804? = 7000 (R) · What is the value of the 5 in 27,547? = 500 (O) · What is the value of the 9 in 569,403? = 9000 (N) · What is the value of the 5 in 68,050? = 50 (C)
- Clue 2 (Addition): "A LEFT HANDED PRINT WAS LEFT ON THE CAPTIVE SHIP"2282 + 4422 = 6704 (A) · 1629 + 2075 = 3704 (H) · 1988 + 2290 = 4278 (L) · 1284 + 2309 = 3593 (V) · 4889 + 3842 = 8731 (C) · 995 + 2301 = 3296 (T) · 2011 + 2504 = 4515 (R) · 2314 + 5228 = 7542 (D) · 4228 + 4387 = 8615 (W) · 2790 + 4570 = 7360 (I) · 4344 + 4362 = 8706 (F) · 1712 + 1141 = 2853 (N) · 1830 + 2833 = 4663 (O) · 907 + 1669 = 2576 (S) · 1684 + 1706 = 3390 (E) · 2287 + 1193 = 3480 (P)
- Clue 3 (Subtraction): "THE SCOUNDREL FLINCHED AT A SWORD OF PURE IRON"5794 - 3950 = 1844 (T) · 8299 - 2710 = 5589 (L) · 10088 - 1428 = 8660 (E) · 4005 - 1247 = 2758 (D) · 2809 - 1248 = 1561 (W) · 8904 - 661 = 8243 (C) · 4305 - 970 = 3335 (N) · 11232 - 4554 = 6678 (R) · 9562 - 577 = 8985 (A) · 3643 - 828 = 2815 (I) · 7786 - 2347 = 5439 (O) · 4722 - 370 = 4352 (H) · 5809 - 3821 = 1988 (P) · 4484 - 650 = 3834 (F) · 2752 - 187 = 2565 (S) · 12087 - 4527 = 7560 (U)
- Clue 4 (Multiplication facts (1-12)): "STRANDS OF SEAWEED GREEN HAIR CAUGHT ON TACKLE"12 × 9 = 108 (S) · 12 × 10 = 120 (W) · 5 × 7 = 35 (A) · 11 × 4 = 44 (F) · 7 × 10 = 70 (I) · 2 × 6 = 12 (U) · 7 × 11 = 77 (R) · 10 × 9 = 90 (T) · 12 × 5 = 60 (G) · 2 × 1 = 2 (O) · 6 × 3 = 18 (L) · 11 × 6 = 66 (H) · 11 × 9 = 99 (K) · 4 × 2 = 8 (C) · 8 × 4 = 32 (D) · 7 × 2 = 14 (E) · 11 × 3 = 33 (N)
- Clue 5 (Missing addends): surviving statement (box 2) → Calico Jack7 + ___ = 8 = 1 · 7 + ___ = 17 = 10 · 39 + ___ = 43 = 4 · 23 + ___ = 26 = 3 · 8 + ___ = 14 = 6 · 38 + ___ = 46 = 8 · 15 + ___ = 24 = 9 · 20 + ___ = 25 = 5 · 7 + ___ = 18 = 11 · 16 + ___ = 23 = 7 · 20 + ___ = 32 = 12
About this mystery
- Grade level
- Grade 7 math
- Math topics
- Place value, Addition, Subtraction, Multiplication, Missing addends
- Reading level
- grades 7-9
- Theme
- The Mystery of Siren Cove — set in Siren Cove and the High Seas
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects