🌊 Unicorns, MermaidsGrade 2Reading: grades 1-2Place valueSubtractionSkip countingAdditionMissing addends
The Mystery of the Coral Crown
A shiny crown has vanished from Rainbow Reef! The sweet sea-unicorns and pretty mermaids are all very sad. Coral the Reef Keeper needs your help. Solve the math puzzles to find out who took the crown!
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 | Magic Trick | Super Spell | Handedness | Hair Color | Biggest Fear |
|---|---|---|---|---|---|
| Shelly | sings sweet shell songs | freezes warm water | holds wand in right hand | pastel pink mane | scared of loud frogs |
| Shimmer | makes bubbles fly | grows giant seaweed | holds wand in left hand | sparkly purple tail | cannot stand sour kelp |
| Ariel | sings sweet shell songs | makes super pink spark | holds wand in left hand | pastel pink mane | cannot stand sour kelp |
| Splash | talks to baby dolphins | summons jelly fish | holds wand in right hand | sparkly purple tail | cannot stand sour kelp |
| Pearl | sings sweet shell songs | summons jelly fish | holds wand in right hand | sparkly purple tail | scared of loud frogs |
| Daphne | glows in the dark | makes super pink spark | holds wand in right hand | pastel pink mane | cannot stand sour kelp |
| Daisy | glows in the dark | freezes warm water | holds wand in left hand | sparkly purple tail | cannot stand sour kelp |
| Glimmer | talks to baby dolphins | summons jelly fish | holds wand in right hand | neon blue hair | scared of loud frogs |
| Nova | glows in the dark | makes super pink spark | holds wand in right hand | sparkly purple tail | cannot stand sour kelp |
| Luna | talks to baby dolphins | heals broken shells | holds wand in left hand | pastel pink mane | sneezes around glitter |
| Sandy | creates rainbow bridges | heals broken shells | holds wand in left hand | neon blue hair | sneezes around glitter |
| Kiko | creates rainbow bridges | heals broken shells | holds wand in right hand | neon blue hair | scared of loud frogs |
| Skye | talks to baby dolphins | freezes warm water | holds wand in right hand | neon blue hair | scared of loud frogs |
| Coral | glows in the dark | makes super pink spark | holds wand in right hand | sparkly purple tail | sneezes around glitter |
| Sparkles | sings sweet shell songs | grows giant seaweed | holds wand in right hand | sparkly purple tail | cannot stand sour kelp |
| Twinkle | makes bubbles fly | freezes warm water | holds wand in right hand | pastel pink mane | sneezes around glitter |
| Melody | sings sweet shell songs | heals broken shells | holds wand in right hand | sparkly purple tail | cannot stand sour kelp |
| Jewel | sings sweet shell songs | heals broken shells | holds wand in left hand | neon blue hair | cannot stand sour kelp |
| Bella | glows in the dark | summons jelly fish | holds wand in right hand | sparkly purple tail | scared of loud frogs |
| Waverly | creates rainbow bridges | makes super pink spark | holds wand in left hand | neon blue hair | cannot stand sour kelp |
| Starla | creates rainbow bridges | makes super pink spark | holds wand in right hand | sparkly purple tail | cannot stand sour kelp |
Clue 1
Place value
We found a locked treasure chest near the sand. The lock needs us to find the number with five tens and three ones. Solve this place value puzzle to open it!
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
12
91
70
58
44
70
29
39
48
25
11
13
13
29
11
44
95
29
44
44
40
T
12
91
70
29
13
23
27
40
39
70
44
58
91
70
13
13
58
What number has 1 ten and 2 ones?T
What number has 4 tens and 0 ones?O
What number has 2 tens and 7 ones?R
What number has 7 tens and 0 ones?E
What number has 4 tens and 8 ones?Y
What number has 1 ten and 3 ones?L
What number has 1 ten and 1 one?I
What number has 9 tens and 1 one?H
What number has 3 tens and 9 ones?K
What number has 2 tens and 9 ones?A
What number has 2 tens and 3 ones?B
What number has 9 tens and 5 ones?C
What number has 2 tens and 5 ones?V
What number has 4 tens and 4 ones?N
What number has 5 tens and 8 ones?S
0/15 letters found
Clue 2
Subtraction
The crook took some shiny sea glass from our pile. We had twelve pieces and now we only have eight. Subtract to find how many are gone and get a new 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
51
13
36
74
28
67
54
55
14
67
17
55
13
37
17
55
T
51
13
48
28
37
25
37
72
T
51
13
17
48
72
34
13
T
51
13
17
25
54
83 - 32 =T
45 - 32 =H
59 - 4 =S
51 - 23 =O
22 - 8 =P
29 - 12 =A
45 - 8 =W
83 - 11 =I
55 - 19 =E
36 - 2 =G
70 - 22 =R
59 - 5 =D
62 - 37 =N
112 - 38 =C
92 - 25 =L
0/15 letters found
Clue 3
Skip counting
Let us walk along the pink path of starfish. We must skip count by fives to reach the cave safely. Count the starfish to find our 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.
T
60
20
9
40
33
36
110
42
9
80
140
8
6
15
9
T
60
20
9
90
6
15
12
36
14
110
36
50
6
18
6
14
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, ___, 65, 70T
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, ___, 16, 18Y
Skip-count by 3s. Fill the blank: 3, 6, ___, 12, 15E
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, ___, 45, 48K
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160P
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70N
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ___, 36, 39O
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, ___, 39, 42U
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, ___, 18, 21D
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, ___, 45, 50S
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, ___, 120, 130R
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110B
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, ___, 90, 100L
Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10A
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, ___, 20, 22W
Skip-count by 3s. Fill the blank: 3, 6, 9, ___, 15, 18G
Skip-count by 2s. Fill the blank: 2, 4, 6, ___, 10, 12M
Skip-count by 5s. Fill the blank: 5, 10, 15, ___, 25, 30H
0/18 letters found
Clue 4
Addition
The mermaids gathered some magic pearls and the unicorns brought some pink flowers. Add them together to see our total and find a hidden note!
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
52
98
48
66
W
52
66
48
77
66
88
60
54
47
77
41
88
77
54
98
56
66
63
54
63
73
56
39
98
W
52
66
56
98
88
35 + 17 =W
18 + 42 =K
22 + 32 =L
46 + 27 =N
34 + 14 =S
20 + 21 =U
36 + 62 =E
27 + 50 =P
11 + 28 =H
23 + 24 =Y
31 + 35 =A
16 + 40 =T
19 + 44 =I
26 + 62 =R
0/14 letters found
Clue 5
Missing addends — the last clue
We need ten shiny shells to open the magic gate. We only have six shells. How many more shells do we need? Solve this to get the final clue!
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
9 + ___ = 20
6 + ___ = 12
3 + ___ = 7
8 + ___ = 10
10 + ___ = 15
9 + ___ = 19
9 + ___ = 12
2 + ___ = 3
4 + ___ = 12
9 + ___ = 18
10 + ___ = 22
Step 2 — cross out the sentence with each answer
1.The villain built a bright rainbow bridge to cross the deep reef, then grew giant seaweed to block the path.
2.The villain sang a sweet shell song to sleep the guards, then called a school of jelly fish for help.
3.The villain whispered to baby dolphins for a fast ride, then froze the warm water into ice blocks.
4.The villain built a bright rainbow bridge to cross the deep reef, then sparked pink light to blind the cameras.
5.The villain sang a sweet shell song to sleep the guards, then sparked pink light to blind the cameras.
6.The villain sang a sweet shell song to sleep the guards, then grew giant seaweed to block the path.
7.The villain glowed brightly to see in the dark cove, then sparked pink light to blind the cameras.
8.The villain blew giant bubbles to float the safe away, then called a school of jelly fish for help.
9.The villain blew giant bubbles to float the safe away, then froze the warm water into ice blocks.
10.The villain built a bright rainbow bridge to cross the deep reef, then healed a broken clam shell to hide the key.
11.The villain whispered to baby dolphins for a fast ride, then called a school of jelly fish for help.
12.The villain blew giant bubbles to float the safe away, then sparked pink light to blind the cameras.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Mystery of the Coral Crown
Culprit: Nova (glows in the dark · makes super pink spark · holds wand in right hand · sparkly purple tail · cannot stand sour kelp)
- Clue 1 (Place value): "THE SNEAKY VILLAIN CANNOT HEAL BROKEN SHELLS"What number has 1 ten and 2 ones? = 12 (T) · What number has 4 tens and 0 ones? = 40 (O) · What number has 2 tens and 7 ones? = 27 (R) · What number has 7 tens and 0 ones? = 70 (E) · What number has 4 tens and 8 ones? = 48 (Y) · What number has 1 ten and 3 ones? = 13 (L) · What number has 1 ten and 1 one? = 11 (I) · What number has 9 tens and 1 one? = 91 (H) · What number has 3 tens and 9 ones? = 39 (K) · What number has 2 tens and 9 ones? = 29 (A) · What number has 2 tens and 3 ones? = 23 (B) · What number has 9 tens and 5 ones? = 95 (C) · What number has 2 tens and 5 ones? = 25 (V) · What number has 4 tens and 4 ones? = 44 (N) · What number has 5 tens and 8 ones? = 58 (S)
- Clue 2 (Subtraction): "THE COLD SPLASH WAS THROWN WITH A RIGHT HAND"83 - 32 = 51 (T) · 45 - 32 = 13 (H) · 59 - 4 = 55 (S) · 51 - 23 = 28 (O) · 22 - 8 = 14 (P) · 29 - 12 = 17 (A) · 45 - 8 = 37 (W) · 83 - 11 = 72 (I) · 55 - 19 = 36 (E) · 36 - 2 = 34 (G) · 70 - 22 = 48 (R) · 59 - 5 = 54 (D) · 62 - 37 = 25 (N) · 112 - 38 = 74 (C) · 92 - 25 = 67 (L)
- Clue 3 (Skip counting): "THE SOUR KELP MADE THE BAD GUY RUN AWAY"Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, ___, 65, 70 = 60 (T) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, ___, 16, 18 = 14 (Y) · Skip-count by 3s. Fill the blank: 3, 6, ___, 12, 15 = 9 (E) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, ___, 45, 48 = 42 (K) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160 = 140 (P) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70 = 50 (N) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ___, 36, 39 = 33 (O) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, ___, 39, 42 = 36 (U) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, ___, 18, 21 = 15 (D) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, ___, 45, 50 = 40 (S) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, ___, 120, 130 = 110 (R) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110 = 90 (B) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, ___, 90, 100 = 80 (L) · Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10 = 6 (A) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, ___, 20, 22 = 18 (W) · Skip-count by 3s. Fill the blank: 3, 6, 9, ___, 15, 18 = 12 (G) · Skip-count by 2s. Fill the blank: 2, 4, 6, ___, 10, 12 = 8 (M) · Skip-count by 5s. Fill the blank: 5, 10, 15, ___, 25, 30 = 20 (H)
- Clue 4 (Addition): "WE SAW A SPARKLY PURPLE TAIL IN THE WATER"35 + 17 = 52 (W) · 18 + 42 = 60 (K) · 22 + 32 = 54 (L) · 46 + 27 = 73 (N) · 34 + 14 = 48 (S) · 20 + 21 = 41 (U) · 36 + 62 = 98 (E) · 27 + 50 = 77 (P) · 11 + 28 = 39 (H) · 23 + 24 = 47 (Y) · 31 + 35 = 66 (A) · 16 + 40 = 56 (T) · 19 + 44 = 63 (I) · 26 + 62 = 88 (R)
- Clue 5 (Missing addends): surviving statement (box 7) → Nova9 + ___ = 20 = 11 · 6 + ___ = 12 = 6 · 3 + ___ = 7 = 4 · 8 + ___ = 10 = 2 · 10 + ___ = 15 = 5 · 9 + ___ = 19 = 10 · 9 + ___ = 12 = 3 · 2 + ___ = 3 = 1 · 4 + ___ = 12 = 8 · 9 + ___ = 18 = 9 · 10 + ___ = 22 = 12
About this mystery
- Grade level
- Grade 2 math
- Math topics
- Place value, Subtraction, Skip counting, Addition, Missing addends
- Reading level
- grades 1-2
- Theme
- The Mystery of the Coral Crown — set in Rainbow Reef
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects