Grade 4Reading: grades 3-4AdditionRoundingSubtractionMultiplicationDivision
The Mystery of Sunken Island
A mysterious rogue explorer broke into the island museum and snatched the golden sun medallion! Track down the clues across the cove to figure 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 | Primary Tool | Special Gear | Dominant Hand | Hair Color | Sensed Weakness |
|---|---|---|---|---|---|
| Jim Hawkins | Bronze Telescope | Smoke Bomb | Right Handed | Blonde Hair | Loud Whistle |
| Ibn Battuta | Signal Lantern | Rope Ladder | Left Handed | Blonde Hair | Squeaky Boots |
| David Livingstone | Pocket Map | Pocket Watch | Right Handed | Blonde Hair | Squeaky Boots |
| Edmund Hillary | Brass Compass | Smoke Bomb | Right Handed | Red Hair | Squeaky Boots |
| Mary Read | Grappling Hook | Map Case | Left Handed | Blonde Hair | Squeaky Boots |
| Marco Polo | Pocket Map | Smoke Bomb | Left Handed | Blonde Hair | Squeaky Boots |
| Ching Shih | Signal Lantern | Pocket Watch | Right Handed | Red Hair | Bright Light |
| Roald Amundsen | Pocket Map | Pocket Watch | Left Handed | Red Hair | Bright Light |
| Amelia Earhart | Bronze Telescope | Pocket Watch | Left Handed | Blonde Hair | Squeaky Boots |
| Anne Bonny | Grappling Hook | Rope Ladder | Left Handed | Blonde Hair | Bright Light |
| Grace O Malley | Grappling Hook | Rope Ladder | Right Handed | Black Hair | Bright Light |
| Lara Croft | Bronze Telescope | Map Case | Left Handed | Blonde Hair | Squeaky Boots |
| Captain Blackbeard | Brass Compass | Smoke Bomb | Right Handed | Blonde Hair | Squeaky Boots |
| Sir Francis Drake | Grappling Hook | Map Case | Right Handed | Blonde Hair | Squeaky Boots |
| Hernan Cortes | Pocket Map | Pocket Watch | Left Handed | Blonde Hair | Loud Whistle |
| Jack Sparrow | Bronze Telescope | Golden Key | Left Handed | Blonde Hair | Bright Light |
| Jacques Cousteau | Signal Lantern | Pocket Watch | Left Handed | Red Hair | Loud Whistle |
| Indiana Jones | Bronze Telescope | Map Case | Right Handed | Blonde Hair | Squeaky Boots |
| Ernest Shackleton | Pocket Map | Smoke Bomb | Left Handed | Red Hair | Squeaky Boots |
| Matthew Henson | Signal Lantern | Map Case | Left Handed | Blonde Hair | Bright Light |
| James Cook | Grappling Hook | Map Case | Left Handed | Blonde Hair | Bright Light |
Clue 1
Addition
You find a torn page from the logbook. Adding up the daily coin counts reveals a secret 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
9517
7468
7685
3206
3920
3206
3366
7685
2918
T
9517
5326
5406
7685
3206
5980
5406
T
9517
2918
5055
3430
3430
7929
5055
3430
5406
3366
7685
4895
5055
5326
5326
7685
3430
2883 + 6634 =T
4700 + 3229 =Y
2106 + 1100 =S
3327 + 1999 =D
2616 + 1304 =U
2200 + 1166 =P
3731 + 3737 =H
2645 + 2250 =L
3026 + 2380 =O
1054 + 1864 =C
4453 + 3232 =E
1906 + 4074 =N
2268 + 1162 =R
2085 + 2970 =A
0/14 letters found
Clue 2
Rounding
The ship sonar display rounds all distance numbers to the nearest ten. Rounding the scanner reading gives you the next 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.
W
290
170
700
110
20
90
90
90
900
W
290
900
30
20
1100
700
5000
900
110
1700
20
1700
3000
170
30
30
900
170
110
Round 288 to the nearest tenW
Round 5,011 to the nearest thousandH
Round 1,132 to the nearest hundredF
Round 864 to the nearest hundredA
Round 1,710 to the nearest hundredD
Round 166 to the nearest tenI
Round 30 to the nearest tenL
Round 114 to the nearest tenN
Round 22 to the nearest tenE
Round 3,223 to the nearest thousandV
Round 89 to the nearest tenS
Round 697 to the nearest hundredT
0/12 letters found
Clue 3
Subtraction
You compare the weight of the empty crate to the full one. Finding the difference uncovers another detail.
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
6209
5261
1377
6482
5083
5911
8852
2713
5261
1377
5911
8852
2713
4929
8212
5083
1377
5911
5406
3641
6742
5054
5054
T
6209
4929
9718 - 3509 =T
5561 - 155 =K
10603 - 3861 =B
9299 - 1087 =Q
5182 - 2469 =D
8778 - 2296 =G
11859 - 3007 =R
1559 - 182 =E
6282 - 1199 =U
8347 - 4706 =Y
5385 - 456 =S
6882 - 1828 =O
6831 - 1570 =H
9825 - 3914 =A
0/14 letters found
Clue 4
Multiplication facts (1-12)
The supply room holds identical stacks of wooden crates. Multiplying the rows gives you the 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.
A
14
11
72
12
77
88
2
84
A
14
36
96
20
54
96
A
14
77
88
132
A
14
20
12
77
54
84
2
72
12
35
63
2 × 7 =A
11 × 8 =D
2 × 1 =E
12 × 7 =H
6 × 6 =I
7 × 5 =C
6 × 12 =L
11 × 12 =W
9 × 6 =T
11 × 7 =N
6 × 2 =O
8 × 12 =R
11 × 1 =B
7 × 9 =K
10 × 2 =S
0/15 letters found
Clue 5
Division facts (1-12) — the last clue
The captain divides the remaining map pieces equally among the scouts to unlock the final message.
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
6 ÷ 2 = ?
50 ÷ 10 = ?
144 ÷ 12 = ?
24 ÷ 12 = ?
12 ÷ 3 = ?
11 ÷ 1 = ?
3 ÷ 3 = ?
45 ÷ 5 = ?
84 ÷ 12 = ?
90 ÷ 9 = ?
12 ÷ 2 = ?
Step 2 — cross out the sentence with each answer
1.The villain lit up the dark hallway with a signal lantern, then unlocked the heavy chest with a golden key.
2.The villain checked the direction on a brass compass, then unlocked the heavy chest with a golden key.
3.The villain scouted ahead with a bronze telescope, then checked the remaining time on a pocket watch.
4.The villain checked the direction on a brass compass, then checked the remaining time on a pocket watch.
5.The villain swung across the gap with a grappling hook, then snatched the ancient paper from the map case.
6.The villain scouted ahead with a bronze telescope, then unlocked the heavy chest with a golden key.
7.The villain swung across the gap with a grappling hook, then climbed down the cliff with a rope ladder.
8.The villain scouted ahead with a bronze telescope, then snatched the ancient paper from the map case.
9.The villain scouted ahead with a bronze telescope, then climbed down the cliff with a rope ladder.
10.The villain studied the secret routes on a pocket map, then snatched the ancient paper from the map case.
11.The villain checked the direction on a brass compass, then snatched the ancient paper from the map case.
12.The villain studied the secret routes on a pocket map, then vanished behind a thick smoke bomb.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Mystery of Sunken Island
Culprit: Lara Croft (Bronze Telescope · Map Case · Left Handed · Blonde Hair · Squeaky Boots)
- Clue 1 (Addition): "THE SUSPECT DOES NOT CARRY A ROPE LADDER"2883 + 6634 = 9517 (T) · 4700 + 3229 = 7929 (Y) · 2106 + 1100 = 3206 (S) · 3327 + 1999 = 5326 (D) · 2616 + 1304 = 3920 (U) · 2200 + 1166 = 3366 (P) · 3731 + 3737 = 7468 (H) · 2645 + 2250 = 4895 (L) · 3026 + 2380 = 5406 (O) · 1054 + 1864 = 2918 (C) · 4453 + 3232 = 7685 (E) · 1906 + 4074 = 5980 (N) · 2268 + 1162 = 3430 (R) · 2085 + 2970 = 5055 (A)
- Clue 2 (Rounding): "WITNESS SAW A LEFT HANDED VILLAIN"Round 288 to the nearest ten = 290 (W) · Round 5,011 to the nearest thousand = 5000 (H) · Round 1,132 to the nearest hundred = 1100 (F) · Round 864 to the nearest hundred = 900 (A) · Round 1,710 to the nearest hundred = 1700 (D) · Round 166 to the nearest ten = 170 (I) · Round 30 to the nearest ten = 30 (L) · Round 114 to the nearest ten = 110 (N) · Round 22 to the nearest ten = 20 (E) · Round 3,223 to the nearest thousand = 3000 (V) · Round 89 to the nearest ten = 90 (S) · Round 697 to the nearest hundred = 700 (T)
- Clue 3 (Subtraction): "THE GUARD HEARD SQUEAKY BOOTS"9718 - 3509 = 6209 (T) · 5561 - 155 = 5406 (K) · 10603 - 3861 = 6742 (B) · 9299 - 1087 = 8212 (Q) · 5182 - 2469 = 2713 (D) · 8778 - 2296 = 6482 (G) · 11859 - 3007 = 8852 (R) · 1559 - 182 = 1377 (E) · 6282 - 1199 = 5083 (U) · 8347 - 4706 = 3641 (Y) · 5385 - 456 = 4929 (S) · 6882 - 1828 = 5054 (O) · 6831 - 1570 = 5261 (H) · 9825 - 3914 = 5911 (A)
- Clue 4 (Multiplication facts (1-12)): "A BLONDE HAIR STRAND WAS ON THE LOCK"2 × 7 = 14 (A) · 11 × 8 = 88 (D) · 2 × 1 = 2 (E) · 12 × 7 = 84 (H) · 6 × 6 = 36 (I) · 7 × 5 = 35 (C) · 6 × 12 = 72 (L) · 11 × 12 = 132 (W) · 9 × 6 = 54 (T) · 11 × 7 = 77 (N) · 6 × 2 = 12 (O) · 8 × 12 = 96 (R) · 11 × 1 = 11 (B) · 7 × 9 = 63 (K) · 10 × 2 = 20 (S)
- Clue 5 (Division facts (1-12)): surviving statement (box 8) → Lara Croft6 ÷ 2 = 3 · 50 ÷ 10 = 5 · 144 ÷ 12 = 12 · 24 ÷ 12 = 2 · 12 ÷ 3 = 4 · 11 ÷ 1 = 11 · 3 ÷ 3 = 1 · 45 ÷ 5 = 9 · 84 ÷ 12 = 7 · 90 ÷ 9 = 10 · 12 ÷ 2 = 6
About this mystery
- Grade level
- Grade 4 math
- Math topics
- Addition, Rounding, Subtraction, Multiplication, Division
- Reading level
- grades 3-4
- Theme
- The Mystery of Sunken Island — set in Sunken Island Cove
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects