🌊 MermaidsGrade 1Reading: grades 1-2AdditionSubtractionSkip countingPlace valueMissing addends
The Mystery of the Missing Rainbow Pearl
The Great Rainbow Pearl is gone! Someone swam into the Royal Reef Palace and snatched it right off the throne. Help the Coral Reef Patrol follow the 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 | Special Move | Sea Buddy | Accessory | Hair Color | Weakness |
|---|---|---|---|---|---|
| Nereus | wave rush | quick dolphin | wears coral ring | blue hair | trapped by nets |
| Glimmer | tail splash | wise sea turtle | wears coral ring | blue hair | trapped by nets |
| Ocean | shell burst | quick dolphin | wears kelp band | green hair | trapped by nets |
| Caspian | bubble swirl | giant octopus | wears coral ring | blue hair | scared of clams |
| Maris | tail splash | tiny seahorse | wears kelp band | green hair | trapped by nets |
| Siren | bubble swirl | quick dolphin | wears kelp band | pink hair | scared of clams |
| Tide | bubble swirl | tiny seahorse | wears kelp band | green hair | trapped by nets |
| Mako | wave rush | friendly crab | wears coral ring | blue hair | scared of clams |
| Opal | bubble swirl | tiny seahorse | wears coral ring | pink hair | tickled by kelp |
| Azure | net throw | quick dolphin | wears kelp band | blue hair | scared of clams |
| Delphina | wave rush | wise sea turtle | wears coral ring | blue hair | scared of clams |
| Pearl | shell burst | giant octopus | wears coral ring | pink hair | trapped by nets |
| Cascade | bubble swirl | giant octopus | wears kelp band | green hair | scared of clams |
| Finley | shell burst | tiny seahorse | wears coral ring | pink hair | scared of clams |
| Breeze | tail splash | wise sea turtle | wears kelp band | pink hair | scared of clams |
| Sandy | tail splash | tiny seahorse | wears kelp band | blue hair | scared of clams |
| Kai | tail splash | friendly crab | wears kelp band | blue hair | trapped by nets |
| Calypso | tail splash | wise sea turtle | wears coral ring | green hair | scared of clams |
| Ripply | shell burst | tiny seahorse | wears kelp band | green hair | scared of clams |
| Marina | bubble swirl | quick dolphin | wears coral ring | blue hair | scared of clams |
| Splash | tail splash | wise sea turtle | wears coral ring | blue hair | scared of clams |
Clue 1
Addition
Marina counts the shiny pearls found in two clam shells to gather clues.
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
20
4
14
5
11
14
3
13
19
T
20
4
10
14
12
9
6
14
5
11
6
T
20
17
5
14
3
16
10
3
11
T
20
6
7
T
20
6
8
17
5
10 + 10 =T
5 + 12 =U
8 + 5 =K
3 + 8 =N
3 + 4 =C
1 + 5 =O
12 + 7 =Y
6 + 2 =P
3 + 2 =S
1 + 2 =A
4 + 8 =F
12 + 4 =G
3 + 7 =I
6 + 8 =E
3 + 1 =H
2 + 7 =D
0/16 letters found
Clue 2
Subtraction
The guard takes away the dropped glowing stones to see how many stay behind.
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
6
1
2
12
17
7
16
16
16
A
6
1
A
6
11
13
2
3
10
12
13
7
14
8
4
13
A
6
5
13
2
17
3
9 - 3 =A
6 - 4 =I
12 - 8 =O
19 - 2 =N
10 - 2 =C
9 - 6 =G
14 - 7 =E
6 - 5 =W
19 - 6 =R
10 - 5 =L
19 - 3 =S
20 - 8 =T
13 - 3 =H
19 - 5 =D
17 - 6 =B
0/15 letters found
Clue 3
Skip counting
Kai skip counts the rows of ocean flowers to follow the thief 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
33
26
45
T
33
26
130
45
120
120
14
50
15
45
12
26
45
8
22
6
130
90
39
25
22
35
27
8
22
28
28
45
60
27
26
70
T
33
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ___, 36, 39T
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70O
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, ___, 24, 26A
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35L
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45M
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, ___, 130, 140F
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110G
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55E
Skip-count by 5s. Fill the blank: 5, 10, ___, 20, 25Z
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, ___, 30, 33S
Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10B
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, ___, 140, 150I
Skip-count by 3s. Fill the blank: 3, 6, 9, ___, 15, 18W
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, ___, 80, 90U
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, ___, 30, 32P
Skip-count by 2s. Fill the blank: 2, 4, 6, ___, 10, 12N
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, ___, 16, 18R
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, ___, 28, 30H
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45C
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, ___, 65, 70D
0/20 letters found
Clue 4
Place value
The deep sea scale shows tens and ones to unlock the secret chest.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
B
88
44
36
30
60
94
B
88
66
57
52
60
74
36
44
56
74
64
64
26
74
30
30
52
69
91
26
94
60
52
68
91
44
74
66
What number has 8 tens and 8 ones?B
What number has 6 tens and 8 ones?C
What number has 5 tens and 7 ones?U
What number has 6 tens and 0 ones?H
What number has 6 tens and 6 ones?L
What number has 6 tens and 9 ones?D
What number has 5 tens and 2 ones?E
What number has 5 tens and 6 ones?W
What number has 2 tens and 6 ones?N
What number has 9 tens and 4 ones?T
What number has 3 tens and 0 ones?G
What number has 4 tens and 4 ones?R
What number has 7 tens and 4 ones?A
What number has 6 tens and 4 ones?S
What number has 3 tens and 6 ones?I
What number has 9 tens and 1 one?O
0/16 letters found
Clue 5
Missing addends — the last clue
Pearl finds how many extra starfish are needed to balance the underwater gate.
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
2 + ___ = 3
6 + ___ = 13
2 + ___ = 12
10 + ___ = 21
7 + ___ = 19
6 + ___ = 8
5 + ___ = 13
2 + ___ = 5
6 + ___ = 11
3 + ___ = 7
9 + ___ = 18
Step 2 — cross out the sentence with each answer
1.The villain surged forward with a wave rush, then hitched a ride on a wise sea turtle.
2.The villain tangled the guard with a net throw, then called upon a friendly crab to help.
3.The villain made a massive tail splash, then swam away alongside a quick dolphin.
4.The villain made a massive tail splash, then called upon a friendly crab to help.
5.The villain blasted open the box with a shell burst, then hitched a ride on a wise sea turtle.
6.The villain surged forward with a wave rush, then called upon a friendly crab to help.
7.The villain created a spinning bubble swirl, then swam away alongside a quick dolphin.
8.The villain tangled the guard with a net throw, then swam away alongside a quick dolphin.
9.The villain created a spinning bubble swirl, then hitched a ride on a wise sea turtle.
10.The villain made a massive tail splash, then hitched a ride on a wise sea turtle.
11.The villain created a spinning bubble swirl, then hid behind a tiny seahorse.
12.The villain created a spinning bubble swirl, then called upon a friendly crab to help.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Mystery of the Missing Rainbow Pearl
Culprit: Mako (wave rush · friendly crab · wears coral ring · blue hair · scared of clams)
- Clue 1 (Addition): "THE SNEAKY THIEF DOES NOT USE A GIANT OCTOPUS"10 + 10 = 20 (T) · 5 + 12 = 17 (U) · 8 + 5 = 13 (K) · 3 + 8 = 11 (N) · 3 + 4 = 7 (C) · 1 + 5 = 6 (O) · 12 + 7 = 19 (Y) · 6 + 2 = 8 (P) · 3 + 2 = 5 (S) · 1 + 2 = 3 (A) · 4 + 8 = 12 (F) · 12 + 4 = 16 (G) · 3 + 7 = 10 (I) · 6 + 8 = 14 (E) · 3 + 1 = 4 (H) · 2 + 7 = 9 (D)
- Clue 2 (Subtraction): "A WITNESS SAW A BRIGHT RED CORAL RING"9 - 3 = 6 (A) · 6 - 4 = 2 (I) · 12 - 8 = 4 (O) · 19 - 2 = 17 (N) · 10 - 2 = 8 (C) · 9 - 6 = 3 (G) · 14 - 7 = 7 (E) · 6 - 5 = 1 (W) · 19 - 6 = 13 (R) · 10 - 5 = 5 (L) · 19 - 3 = 16 (S) · 20 - 8 = 12 (T) · 13 - 3 = 10 (H) · 19 - 5 = 14 (D) · 17 - 6 = 11 (B)
- Clue 3 (Skip counting): "THE THIEF FROZE WHEN A BIG CLAM SNAPPED SHUT"Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ___, 36, 39 = 33 (T) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70 = 50 (O) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, ___, 24, 26 = 22 (A) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35 = 25 (L) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45 = 35 (M) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, ___, 130, 140 = 120 (F) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110 = 90 (G) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55 = 45 (E) · Skip-count by 5s. Fill the blank: 5, 10, ___, 20, 25 = 15 (Z) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, ___, 30, 33 = 27 (S) · Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10 = 6 (B) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, ___, 140, 150 = 130 (I) · Skip-count by 3s. Fill the blank: 3, 6, 9, ___, 15, 18 = 12 (W) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, ___, 80, 90 = 70 (U) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, ___, 30, 32 = 28 (P) · Skip-count by 2s. Fill the blank: 2, 4, 6, ___, 10, 12 = 8 (N) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, ___, 16, 18 = 14 (R) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, ___, 28, 30 = 26 (H) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45 = 39 (C) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, ___, 65, 70 = 60 (D)
- Clue 4 (Place value): "BRIGHT BLUE HAIR WAS SNAGGED ON THE CORAL"What number has 8 tens and 8 ones? = 88 (B) · What number has 6 tens and 8 ones? = 68 (C) · What number has 5 tens and 7 ones? = 57 (U) · What number has 6 tens and 0 ones? = 60 (H) · What number has 6 tens and 6 ones? = 66 (L) · What number has 6 tens and 9 ones? = 69 (D) · What number has 5 tens and 2 ones? = 52 (E) · What number has 5 tens and 6 ones? = 56 (W) · What number has 2 tens and 6 ones? = 26 (N) · What number has 9 tens and 4 ones? = 94 (T) · What number has 3 tens and 0 ones? = 30 (G) · What number has 4 tens and 4 ones? = 44 (R) · What number has 7 tens and 4 ones? = 74 (A) · What number has 6 tens and 4 ones? = 64 (S) · What number has 3 tens and 6 ones? = 36 (I) · What number has 9 tens and 1 one? = 91 (O)
- Clue 5 (Missing addends): surviving statement (box 6) → Mako2 + ___ = 3 = 1 · 6 + ___ = 13 = 7 · 2 + ___ = 12 = 10 · 10 + ___ = 21 = 11 · 7 + ___ = 19 = 12 · 6 + ___ = 8 = 2 · 5 + ___ = 13 = 8 · 2 + ___ = 5 = 3 · 6 + ___ = 11 = 5 · 3 + ___ = 7 = 4 · 9 + ___ = 18 = 9
About this mystery
- Grade level
- Grade 1 math
- Math topics
- Addition, Subtraction, Skip counting, Place value, Missing addends
- Reading level
- grades 1-2
- Theme
- The Mystery of the Missing Rainbow Pearl — set in Coral Creek Lagoon
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects