🌊 MermaidsGrade 5Reading: grades 3-4Fractions of a numberWord problemsOrder of operationsMultiplicationDivision
The Mystery of the Missing Neptune Crown
Someone snuck into the royal vault and took the ancient Neptune Crown! Search the coral reef for clues and catch the culprit.
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 | Pearl Magic | Sea Companion | Flippers | Fin Color | Dislike |
|---|---|---|---|---|---|
| Nerida | Coral Glow | Seahorse | Left Flipper | Emerald Green Fin | Bright Shells |
| Coralie | Current Dash | Sea Turtle | Left Flipper | Ruby Red Fin | Loud Whistles |
| Sandy | Water Shield | Sea Turtle | Left Flipper | Ruby Red Fin | Bright Shells |
| Maris | Water Shield | Seahorse | Left Flipper | Sapphire Blue Fin | Loud Whistles |
| Muriel | Wave Blast | Seahorse | Right Flipper | Sapphire Blue Fin | Tickly Kelp |
| Waverly | Current Dash | Starfish | Right Flipper | Ruby Red Fin | Loud Whistles |
| Posey | Tide Call | Starfish | Right Flipper | Sapphire Blue Fin | Bright Shells |
| Tidal | Current Dash | Seahorse | Right Flipper | Sapphire Blue Fin | Loud Whistles |
| Triton | Coral Glow | Dolphin | Right Flipper | Ruby Red Fin | Loud Whistles |
| Finneas | Coral Glow | Seahorse | Right Flipper | Emerald Green Fin | Loud Whistles |
| Delphina | Wave Blast | Sea Turtle | Right Flipper | Ruby Red Fin | Loud Whistles |
| Azure | Current Dash | Dolphin | Right Flipper | Sapphire Blue Fin | Loud Whistles |
| Caspian | Coral Glow | Seahorse | Left Flipper | Ruby Red Fin | Tickly Kelp |
| Kai | Wave Blast | Starfish | Right Flipper | Sapphire Blue Fin | Tickly Kelp |
| Brook | Coral Glow | Starfish | Right Flipper | Ruby Red Fin | Bright Shells |
| Pearl | Wave Blast | Seahorse | Right Flipper | Ruby Red Fin | Loud Whistles |
| Coralina | Coral Glow | Seahorse | Left Flipper | Ruby Red Fin | Loud Whistles |
| Marina | Water Shield | Manta Ray | Right Flipper | Ruby Red Fin | Tickly Kelp |
| Cove | Coral Glow | Seahorse | Right Flipper | Ruby Red Fin | Loud Whistles |
| Shellie | Current Dash | Sea Turtle | Right Flipper | Ruby Red Fin | Bright Shells |
| Atlantis | Water Shield | Seahorse | Left Flipper | Ruby Red Fin | Tickly Kelp |
Clue 1
Fractions of a number
The Pearl Keeper counted supplies scattered around the royal palace after the breach.
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
22
36
39
34
3
26
26
32
3
28
18
10
39
4
28
10
T
22
36
32
34
39
32
18
10
26
16
36
3
28
5/10 of 44 =T
1/6 of 60 =O
5/10 of 52 =L
1/2 of 72 =H
5/10 of 6 =I
3/6 of 68 =V
2/6 of 96 =A
1/4 of 16 =S
3/5 of 30 =D
3/4 of 52 =E
2/5 of 40 =P
4/5 of 35 =N
0/12 letters found
Clue 2
Word problems
A sea turtle helper analyzed fractions of the pearl collection left in the treasure vault.
Solve each problem to learn its letter, then write the letters in the boxes to fill in the missing word.
Awitnesssawthevillainwas .
R
108
98
10
30
69
117
40
98
P
P
E
R
108
Royal Guard found 105 coral coins yesterday and 3 more today. How many coral coins in all?R
There were 103 glowing pearls. 5 were used up. How many glowing pearls are left?I
There were 151 kelp scrolls. 34 were used up. How many kelp scrolls are left?F
Royal Guard found 67 glowing pearls yesterday and 2 more today. How many glowing pearls in all?T
Royal Guard found 3 shiny shells yesterday and 27 more today. How many shiny shells in all?H
There were 45 kelp scrolls. 5 were used up. How many kelp scrolls are left?L
There were 35 kelp scrolls. 25 were used up. How many kelp scrolls are left?G
0/7 letters found
Clue 3
Order of operations
To unlock the ancient underwater safe, the detective followed steps in a multi-step 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.
T
59
70
51
13
16
68
68
35
16
27
53
68
51
6
53
14
54
22
68
54
39
6
23
70
16
10
T
59
68
51
10
41 + 9 × 2 =T
2 + 2 × 6 =R
2 × 5 - 4 =D
38 + 4 × 4 =O
5 × 10 - 27 =W
8 + 9 × 3 =A
9 + 5 × 6 =U
8 × 7 - 3 =F
14 + 6 × 9 =L
45 + 5 × 5 =H
33 + 9 × 2 =E
6 + 3 × 7 =N
6 + 8 × 2 =M
6 + 5 × 2 =I
6 × 3 - 5 =V
4 + 3 × 2 =S
0/16 letters found
Clue 4
Multiplication facts (1-12)
The guard checked rows of glowing clam shells lined up along the coral reef.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
F
54
121
45
60
77
90
70
45
110
42
70
32
77
F
54
108
60
99
55
90
84
32
6 × 9 =F
11 × 11 =O
7 × 12 =L
10 × 6 =N
4 × 8 =E
7 × 11 =D
9 × 12 =I
11 × 9 =S
6 × 7 =Y
10 × 11 =B
11 × 5 =C
5 × 9 =U
10 × 9 =A
7 × 10 =R
0/14 letters found
Clue 5
Division facts (1-12) — the last clue
The royal guards split the remaining sea glass tokens evenly among the patrols.
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
90 ÷ 10 = ?
6 ÷ 3 = ?
132 ÷ 11 = ?
132 ÷ 12 = ?
90 ÷ 9 = ?
6 ÷ 1 = ?
96 ÷ 12 = ?
42 ÷ 6 = ?
10 ÷ 2 = ?
6 ÷ 2 = ?
7 ÷ 7 = ?
Step 2 — cross out the sentence with each answer
1.The villain blasted waves across the reef, then escaped alongside a dolphin.
2.The villain lit up the coral glow, then hitched a ride with a seahorse.
3.The villain called upon the ocean tide, then hitched a ride with a seahorse.
4.The villain blasted waves across the reef, then swam away with a sea turtle.
5.The villain raised a water shield, then hitched a ride with a seahorse.
6.The villain lit up the coral glow, then snuck away with a starfish.
7.The villain lit up the coral glow, then glided off with a manta ray.
8.The villain called upon the ocean tide, then escaped alongside a dolphin.
9.The villain blasted waves across the reef, then hitched a ride with a seahorse.
10.The villain called upon the ocean tide, then swam away with a sea turtle.
11.The villain dashed through swift currents, then swam away with a sea turtle.
12.The villain dashed through swift currents, then snuck away with a starfish.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Mystery of the Missing Neptune Crown
Culprit: Delphina (Wave Blast · Sea Turtle · Right Flipper · Ruby Red Fin · Loud Whistles)
- Clue 1 (Fractions of a number): "THE VILLAIN DOES NOT HAVE A DOLPHIN"5/10 of 44 = 22 (T) · 1/6 of 60 = 10 (O) · 5/10 of 52 = 26 (L) · 1/2 of 72 = 36 (H) · 5/10 of 6 = 3 (I) · 3/6 of 68 = 34 (V) · 2/6 of 96 = 32 (A) · 1/4 of 16 = 4 (S) · 3/5 of 30 = 18 (D) · 3/4 of 52 = 39 (E) · 2/5 of 40 = 16 (P) · 4/5 of 35 = 28 (N)
- Clue 2 (Word problems): "RIGHT FLIPPER"Royal Guard found 105 coral coins yesterday and 3 more today. How many coral coins in all? = 108 (R) · There were 103 glowing pearls. 5 were used up. How many glowing pearls are left? = 98 (I) · There were 151 kelp scrolls. 34 were used up. How many kelp scrolls are left? = 117 (F) · Royal Guard found 67 glowing pearls yesterday and 2 more today. How many glowing pearls in all? = 69 (T) · Royal Guard found 3 shiny shells yesterday and 27 more today. How many shiny shells in all? = 30 (H) · There were 45 kelp scrolls. 5 were used up. How many kelp scrolls are left? = 40 (L) · There were 35 kelp scrolls. 25 were used up. How many kelp scrolls are left? = 10 (G)
- Clue 3 (Order of operations): "THE VILLAIN FLED FROM LOUD WHISTLES"41 + 9 × 2 = 59 (T) · 2 + 2 × 6 = 14 (R) · 2 × 5 - 4 = 6 (D) · 38 + 4 × 4 = 54 (O) · 5 × 10 - 27 = 23 (W) · 8 + 9 × 3 = 35 (A) · 9 + 5 × 6 = 39 (U) · 8 × 7 - 3 = 53 (F) · 14 + 6 × 9 = 68 (L) · 45 + 5 × 5 = 70 (H) · 33 + 9 × 2 = 51 (E) · 6 + 3 × 7 = 27 (N) · 6 + 8 × 2 = 22 (M) · 6 + 5 × 2 = 16 (I) · 6 × 3 - 5 = 13 (V) · 4 + 3 × 2 = 10 (S)
- Clue 4 (Multiplication facts (1-12)): "FOUND A RUBY RED FIN SCALE"6 × 9 = 54 (F) · 11 × 11 = 121 (O) · 7 × 12 = 84 (L) · 10 × 6 = 60 (N) · 4 × 8 = 32 (E) · 7 × 11 = 77 (D) · 9 × 12 = 108 (I) · 11 × 9 = 99 (S) · 6 × 7 = 42 (Y) · 10 × 11 = 110 (B) · 11 × 5 = 55 (C) · 5 × 9 = 45 (U) · 10 × 9 = 90 (A) · 7 × 10 = 70 (R)
- Clue 5 (Division facts (1-12)): surviving statement (box 4) → Delphina90 ÷ 10 = 9 · 6 ÷ 3 = 2 · 132 ÷ 11 = 12 · 132 ÷ 12 = 11 · 90 ÷ 9 = 10 · 6 ÷ 1 = 6 · 96 ÷ 12 = 8 · 42 ÷ 6 = 7 · 10 ÷ 2 = 5 · 6 ÷ 2 = 3 · 7 ÷ 7 = 1
About this mystery
- Grade level
- Grade 5 math
- Math topics
- Fractions of a number, Word problems, Order of operations, Multiplication, Division
- Reading level
- grades 3-4
- Theme
- The Mystery of the Missing Neptune Crown — set in The Coral Kingdom of Aquaria
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects