🌊 MermaidsGrade 2Reading: grades 1-2Place valueAdditionSubtractionSkip countingMissing addends
The Great Pearl Heist
Oh no! The Royal Pearl is gone. Someone swam into the Pearl Keeper's cave and took it. We must find the Shadow Thief!
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 | Ocean Magic | Trinket | Swimming Tail | Hair Color | Secret Weakness |
|---|---|---|---|---|---|
| Splash | wave dashes | a pearl crown | right fin swimmer | starfish pink | loud whale song |
| Coral | shell shields | a kelp lasso | left fin swimmer | starfish pink | loud whale song |
| Triton | glow bubbles | a seashell horn | left fin swimmer | coral orange | loud whale song |
| Piper | wave dashes | a silver trident | left fin swimmer | coral orange | tickly sand |
| Mami | coral leaps | a kelp lasso | left fin swimmer | starfish pink | bright light |
| Gemma | kelp tangles | a pearl crown | left fin swimmer | seaweed green | loud whale song |
| Nerida | shell shields | a kelp lasso | left fin swimmer | starfish pink | bright light |
| Ariel | glow bubbles | a seashell horn | right fin swimmer | starfish pink | tickly sand |
| Kai | wave dashes | a kelp lasso | left fin swimmer | starfish pink | tickly sand |
| Cleo | wave dashes | a seashell horn | right fin swimmer | seaweed green | loud whale song |
| Wave | coral leaps | a pearl crown | right fin swimmer | seaweed green | loud whale song |
| Delphine | glow bubbles | a seashell horn | left fin swimmer | seaweed green | loud whale song |
| Cora | coral leaps | a seashell horn | left fin swimmer | starfish pink | tickly sand |
| Shelly | shell shields | a seashell horn | left fin swimmer | seaweed green | bright light |
| Wade | shell shields | a silver trident | left fin swimmer | seaweed green | loud whale song |
| Blue | coral leaps | a golden comb | left fin swimmer | starfish pink | bright light |
| Sunny | coral leaps | a golden comb | right fin swimmer | seaweed green | tickly sand |
| Pearl | kelp tangles | a silver trident | left fin swimmer | seaweed green | loud whale song |
| Brooke | glow bubbles | a kelp lasso | left fin swimmer | seaweed green | bright light |
| Sandy | kelp tangles | a golden comb | left fin swimmer | starfish pink | tickly sand |
| Marina | glow bubbles | a golden comb | left fin swimmer | seaweed green | loud whale song |
Clue 1
Place value
The Pearl Keeper has a digital seashell that counts pearls. To unlock the first clue, we need to find how many tens and ones are in this pearl pattern.
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
28
80
42
T
28
80
63
42
18
78
35
42
55
16
35
T
28
80
33
11
42
33
13
42
33
96
41
71
96
35
73
16
What number has 2 tens and 8 ones?T
What number has 3 tens and 5 ones?O
What number has 7 tens and 8 ones?D
What number has 5 tens and 5 ones?S
What number has 1 ten and 8 ones?F
What number has 1 ten and 1 one?V
What number has 4 tens and 2 ones?E
What number has 9 tens and 6 ones?R
What number has 6 tens and 3 ones?I
What number has 3 tens and 3 ones?A
What number has 7 tens and 3 ones?W
What number has 4 tens and 1 one?L
What number has 1 ten and 3 ones?P
What number has 7 tens and 1 one?C
What number has 8 tens and 0 ones?H
What number has 1 ten and 6 ones?N
0/16 letters found
Clue 2
Addition
We found some starfish near the cave. Let us add the group on the left and the group on the right to get the magic sum.
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
90
25
77
50
54
55
31
89
T
90
69
T
90
25
77
91
77
84
T
90
54
61
74
77
69
30
91
50
38 + 52 =T
35 + 39 =D
22 + 9 =A
21 + 29 =Y
41 + 43 =F
17 + 37 =S
43 + 18 =I
11 + 19 =N
17 + 8 =H
29 + 62 =L
39 + 16 =W
27 + 42 =O
59 + 30 =M
23 + 54 =E
0/14 letters found
Clue 3
Subtraction
A school of friendly clownfish wants to help. Some swam away, and we must subtract to see how many are left to guide us.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
P
12
59
45
16
45
59
83
15
55
27
53
45
59
47
14
83
85
19
65
83
14
65
83
P
12
65
53
47
23
30 - 18 =P
89 - 6 =O
71 - 18 =H
43 - 28 =U
101 - 16 =N
79 - 34 =A
72 - 7 =T
34 - 7 =W
77 - 22 =D
47 - 31 =Y
75 - 16 =L
48 - 1 =E
18 - 4 =S
43 - 24 =G
42 - 19 =M
0/15 letters found
Clue 4
Skip counting
To cross the deep trench, we must hop on the glowing coral blocks. Let us count the blocks by fives to reach the next clue safely.
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
25
42
T
33
25
21
42
14
90
42
14
T
33
39
42
20
28
42
42
65
36
22
42
42
24
25
20
21
22
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ___, 36, 39T
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, ___, 22, 24A
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, ___, 26, 28N
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, ___, 45, 48E
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45S
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, ___, 39, 42G
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, ___, 24, 26R
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, ___, 16, 18F
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110L
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35H
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27I
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75D
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, ___, 30, 32W
0/13 letters found
Clue 5
Missing addends — the last clue
We have a small treasure chest that holds ten shiny shells. We only have six now, so let us find how many more we need to open it.
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 + ___ = 10
10 + ___ = 20
10 + ___ = 15
1 + ___ = 7
6 + ___ = 13
6 + ___ = 10
4 + ___ = 13
3 + ___ = 15
8 + ___ = 11
2 + ___ = 3
9 + ___ = 20
Step 2 — cross out the sentence with each answer
1.The villain uses kelp tangles to block paths, then throws a kelp lasso.
2.The villain shoots glow bubbles to hide, then blows a seashell horn.
3.The villain shoots glow bubbles to hide, then throws a kelp lasso.
4.The villain shoots glow bubbles to hide, then swings a silver trident.
5.The villain raises shell shields to escape, then swings a silver trident.
6.The villain makes huge wave dashes to flee, then drops a golden comb.
7.The villain raises shell shields to escape, then loses a pearl crown.
8.The villain shoots glow bubbles to hide, then drops a golden comb.
9.The villain shoots glow bubbles to hide, then loses a pearl crown.
10.The villain uses kelp tangles to block paths, then swings a silver trident.
11.The villain makes huge wave dashes to flee, then blows a seashell horn.
12.The villain makes huge wave dashes to flee, then swings a silver trident.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Great Pearl Heist
Culprit: Delphine (glow bubbles · a seashell horn · left fin swimmer · seaweed green · loud whale song)
- Clue 1 (Place value): "THE THIEF DOES NOT HAVE A PEARL CROWN"What number has 2 tens and 8 ones? = 28 (T) · What number has 3 tens and 5 ones? = 35 (O) · What number has 7 tens and 8 ones? = 78 (D) · What number has 5 tens and 5 ones? = 55 (S) · What number has 1 ten and 8 ones? = 18 (F) · What number has 1 ten and 1 one? = 11 (V) · What number has 4 tens and 2 ones? = 42 (E) · What number has 9 tens and 6 ones? = 96 (R) · What number has 6 tens and 3 ones? = 63 (I) · What number has 3 tens and 3 ones? = 33 (A) · What number has 7 tens and 3 ones? = 73 (W) · What number has 4 tens and 1 one? = 41 (L) · What number has 1 ten and 3 ones? = 13 (P) · What number has 7 tens and 1 one? = 71 (C) · What number has 8 tens and 0 ones? = 80 (H) · What number has 1 ten and 6 ones? = 16 (N)
- Clue 2 (Addition): "THEY SWAM TO THE LEFT SIDE ONLY"38 + 52 = 90 (T) · 35 + 39 = 74 (D) · 22 + 9 = 31 (A) · 21 + 29 = 50 (Y) · 41 + 43 = 84 (F) · 17 + 37 = 54 (S) · 43 + 18 = 61 (I) · 11 + 19 = 30 (N) · 17 + 8 = 25 (H) · 29 + 62 = 91 (L) · 39 + 16 = 55 (W) · 27 + 42 = 69 (O) · 59 + 30 = 89 (M) · 23 + 54 = 77 (E)
- Clue 3 (Subtraction): "PLAY A LOUD WHALE SONG TO STOP THEM"30 - 18 = 12 (P) · 89 - 6 = 83 (O) · 71 - 18 = 53 (H) · 43 - 28 = 15 (U) · 101 - 16 = 85 (N) · 79 - 34 = 45 (A) · 72 - 7 = 65 (T) · 34 - 7 = 27 (W) · 77 - 22 = 55 (D) · 47 - 31 = 16 (Y) · 75 - 16 = 59 (L) · 48 - 1 = 47 (E) · 18 - 4 = 14 (S) · 43 - 24 = 19 (G) · 42 - 19 = 23 (M)
- Clue 4 (Skip counting): "THE THIEF LEFT SEAWEED GREEN HAIR"Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ___, 36, 39 = 33 (T) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, ___, 22, 24 = 20 (A) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, ___, 26, 28 = 24 (N) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, ___, 45, 48 = 42 (E) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45 = 39 (S) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, ___, 39, 42 = 36 (G) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, ___, 24, 26 = 22 (R) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, ___, 16, 18 = 14 (F) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110 = 90 (L) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35 = 25 (H) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27 = 21 (I) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75 = 65 (D) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, ___, 30, 32 = 28 (W)
- Clue 5 (Missing addends): surviving statement (box 2) → Delphine2 + ___ = 10 = 8 · 10 + ___ = 20 = 10 · 10 + ___ = 15 = 5 · 1 + ___ = 7 = 6 · 6 + ___ = 13 = 7 · 6 + ___ = 10 = 4 · 4 + ___ = 13 = 9 · 3 + ___ = 15 = 12 · 8 + ___ = 11 = 3 · 2 + ___ = 3 = 1 · 9 + ___ = 20 = 11
About this mystery
- Grade level
- Grade 2 math
- Math topics
- Place value, Addition, Subtraction, Skip counting, Missing addends
- Reading level
- grades 1-2
- Theme
- The Great Pearl Heist — set in Sparkle Reef
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects