Grade 4Reading: grades 3-4AdditionRoundingSubtractionMultiplicationDivision
The Coral Cove Treasure Mystery
Someone snagged the golden sea turtle statue from the sunken research station! Detective Reef must search the seafloor for clues to catch the robber.
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 | Tool Used | Dominant Hand | Helmet Color | Foiled By |
|---|---|---|---|---|---|
| Mariner Marina | Bubble Shield | Laser Torch | Right Handed | Bright Orange Helmet | Loud Whistles |
| Fisher Finn | Bubble Shield | Ocean Scooter | Left Handed | Seafoam Green Helmet | Loud Whistles |
| Submariner Scott | Hydro-Jet Pack | Treasure Radar | Right Handed | Bright Orange Helmet | Sticky Seaweed |
| Pilot Pearl | Electric Net | Night Goggles | Left Handed | Neon Blue Helmet | Bright Flashlights |
| Tide Tim | Hydro-Jet Pack | Night Goggles | Left Handed | Neon Blue Helmet | Bright Flashlights |
| Captain Sandy | Bubble Shield | Laser Torch | Left Handed | Bright Orange Helmet | Loud Whistles |
| Sailor Maya | Hydro-Jet Pack | Camouflage Suit | Left Handed | Bright Orange Helmet | Sticky Seaweed |
| Harbor Holly | Grappling Anchor | Ocean Scooter | Left Handed | Bright Orange Helmet | Loud Whistles |
| Coastline Chloe | Electric Net | Treasure Radar | Right Handed | Bright Orange Helmet | Bright Flashlights |
| Ocean Olivia | Electric Net | Night Goggles | Right Handed | Neon Blue Helmet | Sticky Seaweed |
| Sailor Sam | Hydro-Jet Pack | Laser Torch | Left Handed | Seafoam Green Helmet | Bright Flashlights |
| Reef Robbie | Hydro-Jet Pack | Treasure Radar | Right Handed | Bright Orange Helmet | Loud Whistles |
| Current Cara | Sonar Blaster | Camouflage Suit | Right Handed | Bright Orange Helmet | Sticky Seaweed |
| Aquanaut Abby | Hydro-Jet Pack | Treasure Radar | Left Handed | Seafoam Green Helmet | Bright Flashlights |
| Commander Coral | Hydro-Jet Pack | Laser Torch | Right Handed | Bright Orange Helmet | Loud Whistles |
| Reef Ray | Sonar Blaster | Night Goggles | Right Handed | Bright Orange Helmet | Loud Whistles |
| Diver Dave | Hydro-Jet Pack | Treasure Radar | Left Handed | Neon Blue Helmet | Loud Whistles |
| Anchor Alex | Hydro-Jet Pack | Camouflage Suit | Right Handed | Bright Orange Helmet | Loud Whistles |
| Navigator Ned | Electric Net | Night Goggles | Left Handed | Bright Orange Helmet | Bright Flashlights |
| Diver Dan | Sonar Blaster | Night Goggles | Right Handed | Seafoam Green Helmet | Loud Whistles |
| Explorer Emma | Electric Net | Ocean Scooter | Left Handed | Neon Blue Helmet | Sticky Seaweed |
Clue 1
Addition
Detective Reef adds up the tally of shell clues left near the submarine hatch.
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
2498
9597
8497
8445
2987
8445
8273
8497
5155
T
2498
2554
4851
8497
8445
6077
4851
T
2498
8020
8497
5278
8646
5278
5155
5278
7573
4851
2987
8274
8297
5278
6555
8497
8445
2987
4814
T
2498
1710 + 788 =T
4789 + 3485 =F
3023 + 1828 =O
3819 + 2736 =G
4215 + 4230 =S
5308 + 2965 =P
3412 + 6185 =H
4233 + 4064 =L
1747 + 1240 =U
4667 + 3830 =E
2538 + 5035 =M
1860 + 2954 =I
1674 + 3604 =A
1106 + 1448 =D
5522 + 3124 =R
2696 + 3381 =N
1700 + 3455 =C
2488 + 5532 =W
0/18 letters found
Clue 2
Rounding
The submarine radar scanner rounds off the sonar signal distance to pinpoint the escape path.
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
2300
110
5000
300
70
300
500
5000
230
T
2300
1100
5000
7000
T
2300
20
30
3700
700
110
T
2300
110
20
290
2000
500
30
3700
290
T
2300
1300
290
700
1100
20
300
300
Round 2,336 to the nearest hundredT
Round 227 to the nearest tenC
Round 66 to the nearest tenU
Round 548 to the nearest hundredP
Round 24 to the nearest tenA
Round 1,260 to the nearest hundredO
Round 651 to the nearest hundredG
Round 3,675 to the nearest hundredI
Round 2,254 to the nearest thousandD
Round 7,480 to the nearest thousandF
Round 290 to the nearest tenN
Round 276 to the nearest hundredS
Round 29 to the nearest tenR
Round 1,121 to the nearest hundredL
Round 5,364 to the nearest thousandE
Round 108 to the nearest tenH
0/16 letters found
Clue 3
Subtraction
Subtracting the leftover air tanks from the original supply shows how long the intruder stayed.
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
6393
5420
8004
1398
3336
1398
1678
8004
7061
T
6393
6760
8717
1398
1398
T
6393
7551
1678
1678
8004
6733
8757
1433
2847
7551
3336
6733
6760
5420
7676
1398
T
6393
2847
8004
1398
10573 - 4180 =T
11155 - 4094 =C
3672 - 2239 =Y
12064 - 4513 =O
9252 - 535 =A
3859 - 1012 =L
9089 - 2356 =D
9207 - 1203 =E
7288 - 3952 =U
11381 - 4621 =W
3304 - 1906 =S
9690 - 933 =B
12336 - 4660 =I
6792 - 1372 =H
5302 - 3624 =P
0/15 letters found
Clue 4
Multiplication facts (1-12)
Counting equal rows of glowing jellyfish helps decode the encrypted lab security grid.
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
49
44
60
84
21
99
99
21
99
99
9
W
49
9
63
35
44
66
33
60
120
35
9
84
66
21
33
21
24
11
21
60
84
21
9
35
63
32
7 × 7 =W
5 × 7 =R
11 × 9 =S
8 × 4 =Y
7 × 12 =N
11 × 1 =M
3 × 7 =E
10 × 12 =O
11 × 4 =I
7 × 9 =B
3 × 11 =H
12 × 5 =T
11 × 6 =G
3 × 3 =A
3 × 8 =L
0/15 letters found
Clue 5
Division facts (1-12) — the last clue
Dividing the salvaged gold coins equally among the bags gives the final lock code.
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
12 ÷ 6 = ?
56 ÷ 8 = ?
44 ÷ 11 = ?
120 ÷ 12 = ?
32 ÷ 4 = ?
55 ÷ 5 = ?
54 ÷ 6 = ?
12 ÷ 1 = ?
12 ÷ 12 = ?
6 ÷ 1 = ?
35 ÷ 7 = ?
Step 2 — cross out the sentence with each answer
1.The villain trapped the guard with an electric net, then found the chest using a treasure radar.
2.The villain zoomed in with a hydro jet pack, then cut the lock with a laser torch.
3.The villain deflected fish with a bubble shield, then cut the lock with a laser torch.
4.The villain blasted a path with sonar, then spotted the vault with night goggles.
5.The villain deflected fish with a bubble shield, then found the chest using a treasure radar.
6.The villain swung down using a grappling anchor, then cut the lock with a laser torch.
7.The villain zoomed in with a hydro jet pack, then found the chest using a treasure radar.
8.The villain deflected fish with a bubble shield, then escaped on an ocean scooter.
9.The villain trapped the guard with an electric net, then cut the lock with a laser torch.
10.The villain deflected fish with a bubble shield, then blended in with a camouflage suit.
11.The villain blasted a path with sonar, then cut the lock with a laser torch.
12.The villain swung down using a grappling anchor, then escaped on an ocean scooter.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Coral Cove Treasure Mystery
Culprit: Mariner Marina (Bubble Shield · Laser Torch · Right Handed · Bright Orange Helmet · Loud Whistles)
- Clue 1 (Addition): "THE SUSPECT DOES NOT WEAR A CAMOUFLAGE SUIT"1710 + 788 = 2498 (T) · 4789 + 3485 = 8274 (F) · 3023 + 1828 = 4851 (O) · 3819 + 2736 = 6555 (G) · 4215 + 4230 = 8445 (S) · 5308 + 2965 = 8273 (P) · 3412 + 6185 = 9597 (H) · 4233 + 4064 = 8297 (L) · 1747 + 1240 = 2987 (U) · 4667 + 3830 = 8497 (E) · 2538 + 5035 = 7573 (M) · 1860 + 2954 = 4814 (I) · 1674 + 3604 = 5278 (A) · 1106 + 1448 = 2554 (D) · 5522 + 3124 = 8646 (R) · 2696 + 3381 = 6077 (N) · 1700 + 3455 = 5155 (C) · 2488 + 5532 = 8020 (W)
- Clue 2 (Rounding): "THE SUSPECT LEFT A RIGHT HAND PRINT ON GLASS"Round 2,336 to the nearest hundred = 2300 (T) · Round 227 to the nearest ten = 230 (C) · Round 66 to the nearest ten = 70 (U) · Round 548 to the nearest hundred = 500 (P) · Round 24 to the nearest ten = 20 (A) · Round 1,260 to the nearest hundred = 1300 (O) · Round 651 to the nearest hundred = 700 (G) · Round 3,675 to the nearest hundred = 3700 (I) · Round 2,254 to the nearest thousand = 2000 (D) · Round 7,480 to the nearest thousand = 7000 (F) · Round 290 to the nearest ten = 290 (N) · Round 276 to the nearest hundred = 300 (S) · Round 29 to the nearest ten = 30 (R) · Round 1,121 to the nearest hundred = 1100 (L) · Round 5,364 to the nearest thousand = 5000 (E) · Round 108 to the nearest ten = 110 (H)
- Clue 3 (Subtraction): "THE SUSPECT WAS STOPPED BY LOUD WHISTLES"10573 - 4180 = 6393 (T) · 11155 - 4094 = 7061 (C) · 3672 - 2239 = 1433 (Y) · 12064 - 4513 = 7551 (O) · 9252 - 535 = 8717 (A) · 3859 - 1012 = 2847 (L) · 9089 - 2356 = 6733 (D) · 9207 - 1203 = 8004 (E) · 7288 - 3952 = 3336 (U) · 11381 - 4621 = 6760 (W) · 3304 - 1906 = 1398 (S) · 9690 - 933 = 8757 (B) · 12336 - 4660 = 7676 (I) · 6792 - 1372 = 5420 (H) · 5302 - 3624 = 1678 (P)
- Clue 4 (Multiplication facts (1-12)): "WITNESSES SAW A BRIGHT ORANGE HELMET NEARBY"7 × 7 = 49 (W) · 5 × 7 = 35 (R) · 11 × 9 = 99 (S) · 8 × 4 = 32 (Y) · 7 × 12 = 84 (N) · 11 × 1 = 11 (M) · 3 × 7 = 21 (E) · 10 × 12 = 120 (O) · 11 × 4 = 44 (I) · 7 × 9 = 63 (B) · 3 × 11 = 33 (H) · 12 × 5 = 60 (T) · 11 × 6 = 66 (G) · 3 × 3 = 9 (A) · 3 × 8 = 24 (L)
- Clue 5 (Division facts (1-12)): surviving statement (box 3) → Mariner Marina12 ÷ 6 = 2 · 56 ÷ 8 = 7 · 44 ÷ 11 = 4 · 120 ÷ 12 = 10 · 32 ÷ 4 = 8 · 55 ÷ 5 = 11 · 54 ÷ 6 = 9 · 12 ÷ 1 = 12 · 12 ÷ 12 = 1 · 6 ÷ 1 = 6 · 35 ÷ 7 = 5
About this mystery
- Grade level
- Grade 4 math
- Math topics
- Addition, Rounding, Subtraction, Multiplication, Division
- Reading level
- grades 3-4
- Theme
- The Coral Cove Treasure Mystery — set in Sunken Trident Reef Research Sub
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects