🏴☠️ PiratesGrade 9Reading: grades 1-2Two-step equationsExponentsSquare rootsIntegers
The Case of the Missing Golden Doubloon
Someone stole the harbor master chest of gold! Solve the math clues to find out who took 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 | Pirate Weapon | Pirate Flag | Bandana Knot | Beard Color | Fear |
|---|---|---|---|---|---|
| Mary Read | Cannon Ball | Crossbone Flag | Left Tied | Black Beard | Afraid Of Water |
| Boatsman Bob | Hook Hand | Kraken Flag | Left Tied | Grey Beard | Afraid Of Water |
| Scurvy Sid | Cannon Ball | Shark Flag | Right Tied | Black Beard | Afraid Of Parrots |
| Anne Bonny | Cutlass | Skull Flag | Left Tied | Black Beard | Afraid Of Cats |
| Calico Jack | Hook Hand | Dragon Flag | Left Tied | Red Beard | Afraid Of Parrots |
| Captain Kidd | Cutlass | Shark Flag | Left Tied | Grey Beard | Afraid Of Parrots |
| Blackbeard | Wooden Sword | Dragon Flag | Left Tied | Grey Beard | Afraid Of Water |
| Barnacle Bill | Cutlass | Kraken Flag | Right Tied | Grey Beard | Afraid Of Water |
| Quartermaster Quinn | Cutlass | Skull Flag | Left Tied | Grey Beard | Afraid Of Water |
| Lookout Lou | Cutlass | Skull Flag | Right Tied | Black Beard | Afraid Of Parrots |
| Navigator Ned | Cutlass | Crossbone Flag | Left Tied | Red Beard | Afraid Of Cats |
| Cannonball Carl | Cutlass | Kraken Flag | Right Tied | Grey Beard | Afraid Of Parrots |
| Pegleg Pete | Wooden Sword | Crossbone Flag | Right Tied | Black Beard | Afraid Of Water |
| Iron Hook Ike | Cannon Ball | Shark Flag | Left Tied | Grey Beard | Afraid Of Water |
| Patchy Pete | Rope Lasso | Shark Flag | Left Tied | Black Beard | Afraid Of Cats |
| Jolly Roger | Wooden Sword | Dragon Flag | Right Tied | Red Beard | Afraid Of Water |
| Stormy Sue | Wooden Sword | Kraken Flag | Left Tied | Red Beard | Afraid Of Parrots |
| Long John | Rope Lasso | Dragon Flag | Left Tied | Grey Beard | Afraid Of Parrots |
| Redbeard | Cannon Ball | Skull Flag | Right Tied | Grey Beard | Afraid Of Water |
| Captain Flint | Cutlass | Kraken Flag | Right Tied | Black Beard | Afraid Of Cats |
| First Mate Faye | Cannon Ball | Skull Flag | Left Tied | Grey Beard | Afraid Of Water |
Clue 1
Two-step equations
A locked treasure box has two dials. Solve to open it and read the 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
12
20
9
18
19
9
6
14
17
4
16
11
6
T
12
9
15
21
9
18
19
21
T
12
3
8
17
6
18
20
6
11
14
3
8
6
10
7x + 2 = 86, x =T
8x + 5 = 133, x =I
2x + 12 = 32, x =G
4x + 9 = 81, x =S
8x + 12 = 164, x =N
6x + 6 = 132, x =O
8x + 5 = 93, x =R
7x + 1 = 120, x =Y
4x + 1 = 57, x =K
6x + 9 = 99, x =D
2x + 2 = 8, x =F
5x + 1 = 41, x =L
3x + 11 = 29, x =A
4x + 2 = 38, x =E
5x + 3 = 23, x =P
2x + 8 = 48, x =H
0/16 letters found
Clue 2
Exponents
The ship flag has a code that grows in powers. Solve it to see the pattern.
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
27
128
243
324
216
256
256
169
216
4
T
27
216
243
343
T
27
128
243
216
9
125
169
4
343
169
4
169
289
4
T
27
128
243
256
243
225
T
27
3^3 =T
5^3 =B
18^2 =V
17^2 =O
15^2 =F
2^7 =H
7^3 =D
3^5 =E
6^3 =I
3^2 =R
13^2 =A
4^4 =L
2^2 =N
0/13 letters found
Clue 3
Square roots
The map has a square grid of islands. Solve to find the side length 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
4
12
8
2
13
19
19
3
13
11
18
17
20
19
16
11
17
T
4
5
8
T
4
13
11
T
4
17
T
4
12
8
18
3
T
4
8
14
sqrt(16) =T
sqrt(361) =L
sqrt(4) =V
sqrt(400) =U
sqrt(64) =E
sqrt(169) =I
sqrt(121) =N
sqrt(9) =A
sqrt(144) =H
sqrt(196) =R
sqrt(289) =O
sqrt(256) =D
sqrt(324) =W
sqrt(25) =G
0/14 letters found
Clue 4
Integers
The ship log tracks gains and losses of gold coins. Solve to find the total.
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
12
13
8
36
34
2
36
A
12
8
31
9
A
12
38
8
33
A
12
5
17
14
7
4
31
14
4
40
9
36
31
36
39
18
9 - (-3) =A
(-14) + 45 =D
10 - (-8) =K
(-10) + 17 =U
(-14) + 16 =B
(-8) + 21 =G
(-6) + 40 =Y
(-15) + 24 =H
(-3) + 11 =R
(-6) + 42 =E
(-14) + 53 =C
14 - (-3) =F
31 - (-2) =W
(-11) + 15 =N
(-3) + 43 =T
(-7) + 12 =S
32 - (-6) =I
(-15) + 29 =O
0/18 letters found
Clue 5
Two-step equations — the last clue
The captain compass needs two steps to unlock. Solve it for the final clue.
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
2x + 12 = 28, x = ?
7x + 9 = 23, x = ?
4x + 1 = 13, x = ?
8x + 11 = 91, x = ?
5x + 4 = 24, x = ?
7x + 10 = 59, x = ?
8x + 12 = 84, x = ?
7x + 7 = 42, x = ?
7x + 12 = 19, x = ?
2x + 8 = 30, x = ?
7x + 6 = 48, x = ?
Step 2 — cross out the sentence with each answer
1.The villain brandished a wooden sword, then hoisted a kraken flag.
2.The villain brandished a wooden sword, then hoisted a dragon flag.
3.The villain rolled a cannon ball, then hoisted a skull flag.
4.The villain swung a rope lasso, then hoisted a dragon flag.
5.The villain swung a cutlass, then hoisted a dragon flag.
6.The villain waved a hook hand, then hoisted a crossbone flag.
7.The villain waved a hook hand, then hoisted a skull flag.
8.The villain swung a cutlass, then hoisted a skull flag.
9.The villain brandished a wooden sword, then hoisted a shark flag.
10.The villain waved a hook hand, then hoisted a dragon flag.
11.The villain swung a cutlass, then hoisted a crossbone flag.
12.The villain waved a hook hand, then hoisted a kraken flag.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Case of the Missing Golden Doubloon
Culprit: Boatsman Bob (Hook Hand · Kraken Flag · Left Tied · Grey Beard · Afraid Of Water)
- Clue 1 (Two-step equations): "THE SNEAKY PIRATE DOES NOT FLY A SHARK FLAG"7x + 2 = 86, x = 12 (T) · 8x + 5 = 133, x = 16 (I) · 2x + 12 = 32, x = 10 (G) · 4x + 9 = 81, x = 18 (S) · 8x + 12 = 164, x = 19 (N) · 6x + 6 = 132, x = 21 (O) · 8x + 5 = 93, x = 11 (R) · 7x + 1 = 120, x = 17 (Y) · 4x + 1 = 57, x = 14 (K) · 6x + 9 = 99, x = 15 (D) · 2x + 2 = 8, x = 3 (F) · 5x + 1 = 41, x = 8 (L) · 3x + 11 = 29, x = 6 (A) · 4x + 2 = 38, x = 9 (E) · 5x + 3 = 23, x = 4 (P) · 2x + 8 = 48, x = 20 (H)
- Clue 2 (Exponents): "THE VILLAIN TIED THEIR BANDANA ON THE LEFT"3^3 = 27 (T) · 5^3 = 125 (B) · 18^2 = 324 (V) · 17^2 = 289 (O) · 15^2 = 225 (F) · 2^7 = 128 (H) · 7^3 = 343 (D) · 3^5 = 243 (E) · 6^3 = 216 (I) · 3^2 = 9 (R) · 13^2 = 169 (A) · 4^4 = 256 (L) · 2^2 = 4 (N)
- Clue 3 (Square roots): "THE VILLAIN WOULD NOT GET INTO THE WATER"sqrt(16) = 4 (T) · sqrt(361) = 19 (L) · sqrt(4) = 2 (V) · sqrt(400) = 20 (U) · sqrt(64) = 8 (E) · sqrt(169) = 13 (I) · sqrt(121) = 11 (N) · sqrt(9) = 3 (A) · sqrt(144) = 12 (H) · sqrt(196) = 14 (R) · sqrt(289) = 17 (O) · sqrt(256) = 16 (D) · sqrt(324) = 18 (W) · sqrt(25) = 5 (G)
- Clue 4 (Integers): "A GREY BEARD HAIR WAS FOUND ON THE DECK"9 - (-3) = 12 (A) · (-14) + 45 = 31 (D) · 10 - (-8) = 18 (K) · (-10) + 17 = 7 (U) · (-14) + 16 = 2 (B) · (-8) + 21 = 13 (G) · (-6) + 40 = 34 (Y) · (-15) + 24 = 9 (H) · (-3) + 11 = 8 (R) · (-6) + 42 = 36 (E) · (-14) + 53 = 39 (C) · 14 - (-3) = 17 (F) · 31 - (-2) = 33 (W) · (-11) + 15 = 4 (N) · (-3) + 43 = 40 (T) · (-7) + 12 = 5 (S) · 32 - (-6) = 38 (I) · (-15) + 29 = 14 (O)
- Clue 5 (Two-step equations): surviving statement (box 12) → Boatsman Bob2x + 12 = 28, x = 8 · 7x + 9 = 23, x = 2 · 4x + 1 = 13, x = 3 · 8x + 11 = 91, x = 10 · 5x + 4 = 24, x = 4 · 7x + 10 = 59, x = 7 · 8x + 12 = 84, x = 9 · 7x + 7 = 42, x = 5 · 7x + 12 = 19, x = 1 · 2x + 8 = 30, x = 11 · 7x + 6 = 48, x = 6
About this mystery
- Grade level
- Grade 9 math
- Math topics
- Two-step equations, Exponents, Square roots, Integers
- Reading level
- grades 1-2
- Theme
- The Case of the Missing Golden Doubloon — set in Barnacle Bay
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects