🌊 MermaidsGrade 6Reading: grades 5-6AdditionSubtractionPercentagesExponentsDivision
The Mystery of the Neptune Pearl
When the shimmering Neptune Pearl vanished from the royal vault, the underwater kingdom fell into chaotic currents. Detective Mer-Sleuth must decode the clues to catch the villain.
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 Ability | Special Trait | Armband Side | Hair Color | Vulnerability |
|---|---|---|---|---|---|
| Cascade | tide surge | animal talk | wears left armband | deep violet | bright flash |
| Marlina | bubble shield | bioluminescence | wears left armband | deep violet | tickle kelp |
| Oceanus | bubble shield | siren song | wears right armband | neon coral | loud whistles |
| Orion | water blast | animal talk | wears right armband | emerald green | loud whistles |
| Coral | water blast | siren song | wears left armband | neon coral | bright flash |
| Marina | current dash | siren song | wears right armband | deep violet | tickle kelp |
| Nerina | water blast | shell armor | wears right armband | deep violet | tickle kelp |
| Coralline | bubble shield | deep vision | wears right armband | emerald green | tickle kelp |
| Delphine | current dash | shell armor | wears left armband | neon coral | bright flash |
| Tide | current dash | bioluminescence | wears left armband | neon coral | tickle kelp |
| Kai | water blast | siren song | wears right armband | deep violet | tickle kelp |
| Alana | kelp whip | bioluminescence | wears left armband | emerald green | tickle kelp |
| Finley | water blast | shell armor | wears left armband | emerald green | tickle kelp |
| Shelly | current dash | shell armor | wears right armband | deep violet | tickle kelp |
| Adella | current dash | bioluminescence | wears right armband | deep violet | tickle kelp |
| Caspian | tide surge | bioluminescence | wears right armband | neon coral | tickle kelp |
| Pearl | water blast | deep vision | wears right armband | deep violet | tickle kelp |
| Ariel | water blast | bioluminescence | wears left armband | deep violet | bright flash |
| Aquata | water blast | siren song | wears right armband | emerald green | bright flash |
| Andrina | kelp whip | animal talk | wears right armband | deep violet | bright flash |
| Triton | current dash | shell armor | wears right armband | deep violet | bright flash |
Clue 1
Addition
Guard Finley tallied the pearl fragments left along two trenches to find the total combined weight.
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
6999
3895
6722
5506
8562
5506
9556
6722
4078
T
6999
7253
5359
6722
5506
4071
5359
T
6999
8562
5506
6722
5506
4603
2672
6722
4071
5506
5359
4071
9060
3434 + 3565 =T
3465 + 3788 =D
2027 + 2051 =C
4037 + 5519 =P
2336 + 4386 =E
2676 + 2830 =S
2713 + 2646 =O
4376 + 4186 =U
1180 + 1492 =R
2250 + 2353 =I
2604 + 1291 =H
5829 + 3231 =G
1610 + 2461 =N
0/13 letters found
Clue 2
Subtraction
Guard Marina measured the vault water level before and after the drain trap was triggered to find the missing depth.
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
1254
4424
6911
1827
4484
1096
1096
1096
5904
W
1254
5904
1827
5904
3848
5562
8903
5904
1827
3097
5012
1827
6911
7842
4484
3848
4424
8908
7842
6911
5904
3848
5562
4651 - 3397 =W
10393 - 3482 =T
5087 - 75 =O
6191 - 3094 =D
6922 - 2438 =E
7951 - 3527 =I
6888 - 984 =A
6938 - 1376 =M
5492 - 1644 =R
9555 - 1713 =H
2543 - 1447 =S
10485 - 1577 =G
9885 - 982 =B
4685 - 2858 =N
0/14 letters found
Clue 3
Percentages
Royal Scout Caspian calculated what percentage of the palace guard was alert during the night patrol.
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
9
35
6
37
31
26
37
26
31
13
30
5
18
14
18
26
39
T
9
12
39
42
35
28
26
T
9
25
26
7
12
3
3
5% of 180 =T
10% of 390 =D
10% of 180 =S
50% of 26 =P
25% of 124 =L
50% of 52 =E
50% of 50 =H
20% of 185 =K
75% of 8 =C
20% of 175 =I
50% of 60 =W
5% of 60 =F
25% of 56 =U
5% of 240 =O
5% of 140 =M
75% of 56 =R
50% of 10 =A
10% of 280 =V
0/18 letters found
Clue 4
Exponents
Archivist Nerina tracked how fast the glowing plankton population multiplied by squared powers each hour.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
D
128
196
196
16
216
9
324
8
196
100
169
49
9
256
4
343
196
256
196
100
256
49
16
16
196
D
128
9
125
256
324
81
400
2^7 =D
3^4 =C
3^2 =I
6^3 =V
16^2 =R
7^3 =W
13^2 =H
5^3 =N
7^2 =A
10^2 =T
20^2 =K
2^2 =S
14^2 =E
18^2 =O
4^2 =P
2^3 =L
0/16 letters found
Clue 5
Division facts (1-12) — the last clue
Captain Triton divided the recovered treasure coins equally among the patrolling mermaid squadrons.
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
77 ÷ 11 = ?
36 ÷ 3 = ?
66 ÷ 6 = ?
24 ÷ 12 = ?
10 ÷ 1 = ?
8 ÷ 2 = ?
96 ÷ 12 = ?
54 ÷ 6 = ?
36 ÷ 6 = ?
3 ÷ 3 = ?
21 ÷ 7 = ?
Step 2 — cross out the sentence with each answer
1.The villain lashes kelp whips, then speaks with sea animals.
2.The villain summons tide surges, then sings enchanting tunes.
3.The villain creates bubble shields, then speaks with sea animals.
4.The villain blasts swirling water, then speaks with sea animals.
5.The villain blasts swirling water, then hardens shell armor.
6.The villain summons tide surges, then hardens shell armor.
7.The villain blasts swirling water, then peers through deep darkness.
8.The villain creates bubble shields, then glows with bioluminescence.
9.The villain creates bubble shields, then peers through deep darkness.
10.The villain lashes kelp whips, then sings enchanting tunes.
11.The villain dashes through currents, then glows with bioluminescence.
12.The villain dashes through currents, then hardens shell armor.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Mystery of the Neptune Pearl
Culprit: Nerina (water blast · shell armor · wears right armband · deep violet · tickle kelp)
- Clue 1 (Addition): "THE SUSPECT DOES NOT USE SIREN SONG"3434 + 3565 = 6999 (T) · 3465 + 3788 = 7253 (D) · 2027 + 2051 = 4078 (C) · 4037 + 5519 = 9556 (P) · 2336 + 4386 = 6722 (E) · 2676 + 2830 = 5506 (S) · 2713 + 2646 = 5359 (O) · 4376 + 4186 = 8562 (U) · 1180 + 1492 = 2672 (R) · 2250 + 2353 = 4603 (I) · 2604 + 1291 = 3895 (H) · 5829 + 3231 = 9060 (G) · 1610 + 2461 = 4071 (N)
- Clue 2 (Subtraction): "WITNESS SAW AN ARMBAND ON THE RIGHT ARM"4651 - 3397 = 1254 (W) · 10393 - 3482 = 6911 (T) · 5087 - 75 = 5012 (O) · 6191 - 3094 = 3097 (D) · 6922 - 2438 = 4484 (E) · 7951 - 3527 = 4424 (I) · 6888 - 984 = 5904 (A) · 6938 - 1376 = 5562 (M) · 5492 - 1644 = 3848 (R) · 9555 - 1713 = 7842 (H) · 2543 - 1447 = 1096 (S) · 10485 - 1577 = 8908 (G) · 9885 - 982 = 8903 (B) · 4685 - 2858 = 1827 (N)
- Clue 3 (Percentages): "TICKLE KELP WAS USED TO DRIVE THEM OFF"5% of 180 = 9 (T) · 10% of 390 = 39 (D) · 10% of 180 = 18 (S) · 50% of 26 = 13 (P) · 25% of 124 = 31 (L) · 50% of 52 = 26 (E) · 50% of 50 = 25 (H) · 20% of 185 = 37 (K) · 75% of 8 = 6 (C) · 20% of 175 = 35 (I) · 50% of 60 = 30 (W) · 5% of 60 = 3 (F) · 25% of 56 = 14 (U) · 5% of 240 = 12 (O) · 5% of 140 = 7 (M) · 75% of 56 = 42 (R) · 50% of 10 = 5 (A) · 10% of 280 = 28 (V)
- Clue 4 (Exponents): "DEEP VIOLET HAIRS WERE TRAPPED IN ROCK"2^7 = 128 (D) · 3^4 = 81 (C) · 3^2 = 9 (I) · 6^3 = 216 (V) · 16^2 = 256 (R) · 7^3 = 343 (W) · 13^2 = 169 (H) · 5^3 = 125 (N) · 7^2 = 49 (A) · 10^2 = 100 (T) · 20^2 = 400 (K) · 2^2 = 4 (S) · 14^2 = 196 (E) · 18^2 = 324 (O) · 4^2 = 16 (P) · 2^3 = 8 (L)
- Clue 5 (Division facts (1-12)): surviving statement (box 5) → Nerina77 ÷ 11 = 7 · 36 ÷ 3 = 12 · 66 ÷ 6 = 11 · 24 ÷ 12 = 2 · 10 ÷ 1 = 10 · 8 ÷ 2 = 4 · 96 ÷ 12 = 8 · 54 ÷ 6 = 9 · 36 ÷ 6 = 6 · 3 ÷ 3 = 1 · 21 ÷ 7 = 3
About this mystery
- Grade level
- Grade 6 math
- Math topics
- Addition, Subtraction, Percentages, Exponents, Division
- Reading level
- grades 5-6
- Theme
- The Mystery of the Neptune Pearl — set in Coral Crest Palace
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects