🌊 Mermaids, UnicornsGrade 1Reading: grades 3-4AdditionSubtractionSkip countingPlace valueMissing addends
The Case of the Missing Star Crystal
Someone swiped the glowing Star Crystal from Coral Crest Lagoon! The mermaids and sea unicorns are in a panic. Detective Splash takes the case to track down the sneaky 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 | Main Skill | Magic Trick | Dominant Hand | Mane Color | Weakness |
|---|---|---|---|---|---|
| Piper Pearl | Wave Dash | Star Float | Left Handed | Purple Mane | Bright Flash |
| River Shine | Tail Whip | Water Whirl | Left Handed | Pink Mane | Sweet Kelp |
| Cleo Current | Tail Whip | Glow Aura | Left Handed | Purple Mane | Sweet Kelp |
| Splash Mane | Bubble Shield | Prism Beam | Left Handed | Purple Mane | Bright Flash |
| Luna Coral | Horn Shine | Star Float | Right Handed | Purple Mane | Sweet Kelp |
| Coral Sparkle | Wave Dash | Star Float | Left Handed | Blue Mane | Loud Bells |
| Sapphire Bay | Bubble Shield | Sonic Song | Right Handed | Purple Mane | Bright Flash |
| Nova Shimmer | Tail Whip | Star Float | Left Handed | Purple Mane | Loud Bells |
| Skye Lagoon | Tail Whip | Water Whirl | Left Handed | Purple Mane | Bright Flash |
| Ocean Star | Glitter Blast | Sonic Song | Right Handed | Blue Mane | Bright Flash |
| Ruby Fin | Horn Shine | Prism Beam | Left Handed | Blue Mane | Sweet Kelp |
| Marina Shell | Horn Shine | Star Float | Right Handed | Purple Mane | Bright Flash |
| Pearl Drift | Glitter Blast | Glow Aura | Right Handed | Blue Mane | Loud Bells |
| Gemma Reef | Tail Whip | Glow Aura | Left Handed | Blue Mane | Sweet Kelp |
| Cascade Breeze | Horn Shine | Prism Beam | Right Handed | Purple Mane | Loud Bells |
| Hazel Harbor | Bubble Shield | Glow Aura | Right Handed | Blue Mane | Bright Flash |
| Misty Horn | Wave Dash | Star Float | Left Handed | Blue Mane | Bright Flash |
| Sunny Tail | Tail Whip | Glow Aura | Left Handed | Purple Mane | Bright Flash |
| Aqua Glow | Glitter Blast | Water Whirl | Left Handed | Pink Mane | Sweet Kelp |
| Indigo Tide | Horn Shine | Prism Beam | Left Handed | Purple Mane | Loud Bells |
| Violet Stream | Wave Dash | Glow Aura | Left Handed | Purple Mane | Bright Flash |
Clue 1
Addition
To start the search Detective Splash counts all the shiny pearls found near the stolen vault
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
2
17
16
12
3
4
7
9
T
2
7
20
16
11
4
20
T
2
14
11
16
18
3
T
2
16
10
18
17
9
10
5
1 + 1 =T
1 + 3 =N
7 + 2 =I
1 + 2 =A
3 + 4 =D
9 + 7 =E
7 + 11 =W
3 + 2 =L
12 + 5 =H
7 + 3 =R
8 + 3 =S
3 + 9 =B
8 + 12 =O
7 + 7 =U
0/14 letters found
Clue 2
Subtraction
Some starfish floated away from the reef so Detective Splash calculates how many remain
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
13
18
12
15
4
6
17
17
17
A
13
18
A
13
19
A
13
4
10
2
4
15
14
6
16
6
9
15
14
A
13
4
10
16 - 3 =A
4 - 2 =O
14 - 2 =I
20 - 2 =W
17 - 2 =T
8 - 2 =E
17 - 3 =H
20 - 3 =S
11 - 7 =N
17 - 7 =D
17 - 1 =L
20 - 1 =B
18 - 9 =F
0/13 letters found
Clue 3
Skip counting
Detective Splash counts glowing sea crystals along the path by skipping in equal groups
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
21
140
6
30
70
70
80
30
90
20
80
35
35
T
33
100
50
50
140
25
15
45
80
15
12
30
8
21
T
33
28
70
80
35
21
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, ___, 8, 10V
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, ___, 30, 32F
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, ___, 110, 120O
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70P
Skip-count by 10s. Fill the blank: 10, 20, ___, 40, 50I
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, ___, 90, 100A
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27H
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, ___, 80, 90L
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110N
Skip-count by 5s. Fill the blank: 5, 10, ___, 20, 25B
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45S
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35D
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160E
Skip-count by 3s. Fill the blank: 3, 6, 9, ___, 15, 18R
Skip-count by 2s. Fill the blank: 2, 4, 6, ___, 10, 12G
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55Y
Skip-count by 5s. Fill the blank: 5, 10, 15, ___, 25, 30W
0/18 letters found
Clue 4
Place value
The magical lock code shows digits for tens and ones on the coral gate screen
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
19
24
29
P
19
22
21
27
57
32
21
28
57
42
29
50
57
11
22
21
61
78
87
32
78
28
21
29
21
21
61
What number has 1 ten and 9 ones?P
What number has 8 tens and 7 ones?O
What number has 5 tens and 7 ones?A
What number has 2 tens and 7 ones?M
What number has 2 tens and 1 one?E
What number has 4 tens and 2 ones?I
What number has 2 tens and 2 ones?L
What number has 7 tens and 8 ones?T
What number has 5 tens and 0 ones?W
What number has 1 ten and 1 one?S
What number has 3 tens and 2 ones?N
What number has 2 tens and 9 ones?R
What number has 2 tens and 4 ones?U
What number has 2 tens and 8 ones?H
What number has 6 tens and 1 one?F
0/15 letters found
Clue 5
Missing addends — the last clue
Detective Splash knows how many shells are needed to fix the bridge and finds what is missing
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
1 + ___ = 3
2 + ___ = 8
2 + ___ = 3
8 + ___ = 17
8 + ___ = 18
2 + ___ = 7
2 + ___ = 14
9 + ___ = 13
8 + ___ = 11
3 + ___ = 10
5 + ___ = 13
Step 2 — cross out the sentence with each answer
1.The villain swung a tail whip, then shone a glow aura.
2.The villain used a wave dash, then used a star float.
3.The villain lit a horn shine, then shone a glow aura.
4.The villain swung a tail whip, then cast a prism beam.
5.The villain swung a tail whip, then used a star float.
6.The villain used a wave dash, then shone a glow aura.
7.The villain used a wave dash, then made a water whirl.
8.The villain used a wave dash, then sang a sonic song.
9.The villain shot a glitter blast, then used a star float.
10.The villain shot a glitter blast, then cast a prism beam.
11.The villain raised a bubble shield, then cast a prism beam.
12.The villain raised a bubble shield, then shone a glow aura.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Case of the Missing Star Crystal
Culprit: Splash Mane (Bubble Shield · Prism Beam · Left Handed · Purple Mane · Bright Flash)
- Clue 1 (Addition): "THE BANDIT DOES NOT USE WATER WHIRL"1 + 1 = 2 (T) · 1 + 3 = 4 (N) · 7 + 2 = 9 (I) · 1 + 2 = 3 (A) · 3 + 4 = 7 (D) · 9 + 7 = 16 (E) · 7 + 11 = 18 (W) · 3 + 2 = 5 (L) · 12 + 5 = 17 (H) · 7 + 3 = 10 (R) · 8 + 3 = 11 (S) · 3 + 9 = 12 (B) · 8 + 12 = 20 (O) · 7 + 7 = 14 (U)
- Clue 2 (Subtraction): "A WITNESS SAW A BAND ON THE LEFT HAND"16 - 3 = 13 (A) · 4 - 2 = 2 (O) · 14 - 2 = 12 (I) · 20 - 2 = 18 (W) · 17 - 2 = 15 (T) · 8 - 2 = 6 (E) · 17 - 3 = 14 (H) · 20 - 3 = 17 (S) · 11 - 7 = 4 (N) · 17 - 7 = 10 (D) · 17 - 1 = 16 (L) · 20 - 1 = 19 (B) · 18 - 9 = 9 (F)
- Clue 3 (Skip counting): "THE VILLAIN WAS STOPPED BY A BRIGHT FLASH"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, ___, 8, 10 = 6 (V) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, ___, 30, 32 = 28 (F) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, ___, 110, 120 = 100 (O) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70 = 50 (P) · Skip-count by 10s. Fill the blank: 10, 20, ___, 40, 50 = 30 (I) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, ___, 90, 100 = 80 (A) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27 = 21 (H) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, ___, 80, 90 = 70 (L) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110 = 90 (N) · Skip-count by 5s. Fill the blank: 5, 10, ___, 20, 25 = 15 (B) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45 = 35 (S) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35 = 25 (D) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160 = 140 (E) · Skip-count by 3s. Fill the blank: 3, 6, 9, ___, 15, 18 = 12 (R) · Skip-count by 2s. Fill the blank: 2, 4, 6, ___, 10, 12 = 8 (G) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55 = 45 (Y) · Skip-count by 5s. Fill the blank: 5, 10, 15, ___, 25, 30 = 20 (W)
- Clue 4 (Place value): "PURPLE MANE HAIR WAS LEFT ON THE REEF"What number has 1 ten and 9 ones? = 19 (P) · What number has 8 tens and 7 ones? = 87 (O) · What number has 5 tens and 7 ones? = 57 (A) · What number has 2 tens and 7 ones? = 27 (M) · What number has 2 tens and 1 one? = 21 (E) · What number has 4 tens and 2 ones? = 42 (I) · What number has 2 tens and 2 ones? = 22 (L) · What number has 7 tens and 8 ones? = 78 (T) · What number has 5 tens and 0 ones? = 50 (W) · What number has 1 ten and 1 one? = 11 (S) · What number has 3 tens and 2 ones? = 32 (N) · What number has 2 tens and 9 ones? = 29 (R) · What number has 2 tens and 4 ones? = 24 (U) · What number has 2 tens and 8 ones? = 28 (H) · What number has 6 tens and 1 one? = 61 (F)
- Clue 5 (Missing addends): surviving statement (box 11) → Splash Mane1 + ___ = 3 = 2 · 2 + ___ = 8 = 6 · 2 + ___ = 3 = 1 · 8 + ___ = 17 = 9 · 8 + ___ = 18 = 10 · 2 + ___ = 7 = 5 · 2 + ___ = 14 = 12 · 9 + ___ = 13 = 4 · 8 + ___ = 11 = 3 · 3 + ___ = 10 = 7 · 5 + ___ = 13 = 8
About this mystery
- Grade level
- Grade 1 math
- Math topics
- Addition, Subtraction, Skip counting, Place value, Missing addends
- Reading level
- grades 3-4
- Theme
- The Case of the Missing Star Crystal — set in Coral Crest Lagoon
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects