🦕 Mermaids, Dinosaurs, RobotsGrade 1Reading: grades 1-2Place valueAdditionSubtractionSkip countingMissing addends
The Cyber-Reef Caper
A sneaky Robo-Raider stole the Golden Pearl! We must track them down in the Cyber-Reef before the power goes out.
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 Power | Extra Tool | Sighting | Head Gear | Weakness |
|---|---|---|---|---|---|
| Raptor-Wave | rocket stomp | mega drill | left claw | seaweed wig | bubbly soap |
| Aqua-Bolts | sonar scream | mega drill | right claw | wire braid | bubbly soap |
| Coral-Claw | turbo tail-fin | rust beam | right claw | coral crown | lemon juice |
| Deep-Drive | laser breath | mega drill | right claw | seaweed wig | giant magnet |
| Wave-Walker | sonar scream | rust beam | right claw | wire braid | giant magnet |
| Steel-Shell | electric bite | oil splash | left claw | seaweed wig | giant magnet |
| Fin-Tin | electric bite | glow net | left claw | coral crown | bubbly soap |
| Dino-Drip | laser breath | oil splash | right claw | seaweed wig | giant magnet |
| Gizmo-Gator | laser breath | bubble shield | left claw | wire braid | giant magnet |
| Glimmer-Byte | laser breath | oil splash | right claw | seaweed wig | bubbly soap |
| Bubbles-9000 | electric bite | oil splash | left claw | coral crown | bubbly soap |
| Shell-Shock | turbo tail-fin | bubble shield | left claw | seaweed wig | bubbly soap |
| Rex-Bot | laser breath | bubble shield | left claw | seaweed wig | lemon juice |
| Pearl-Plug | electric bite | oil splash | left claw | seaweed wig | bubbly soap |
| Tricera-Splash | electric bite | bubble shield | left claw | seaweed wig | lemon juice |
| Rusty-Scales | rocket stomp | glow net | left claw | seaweed wig | lemon juice |
| Siren-Circuit | laser breath | glow net | left claw | coral crown | bubbly soap |
| Sparky-Shark | electric bite | rust beam | right claw | wire braid | lemon juice |
| T-Reef | turbo tail-fin | rust beam | left claw | seaweed wig | bubbly soap |
| Marina-Gear | sonar scream | oil splash | left claw | wire braid | giant magnet |
| Mega-Mouth | rocket stomp | glow net | left claw | seaweed wig | bubbly soap |
Clue 1
Place value
We find a locked computer screen. To open it, we must count the tens and ones blocks.
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
71
44
65
88
47
92
92
35
47
13
33
68
65
34
13
68
T
71
89
34
65
T
71
44
65
38
89
34
T
71
98
65
35
41
What number has 7 tens and 1 one?T
What number has 3 tens and 4 ones?S
What number has 4 tens and 4 ones?H
What number has 3 tens and 5 ones?A
What number has 4 tens and 7 ones?I
What number has 4 tens and 1 one?M
What number has 9 tens and 2 ones?L
What number has 8 tens and 9 ones?U
What number has 9 tens and 8 ones?B
What number has 6 tens and 8 ones?O
What number has 3 tens and 3 ones?D
What number has 3 tens and 8 ones?R
What number has 1 ten and 3 ones?N
What number has 6 tens and 5 ones?E
What number has 8 tens and 8 ones?V
0/15 letters found
Clue 2
Addition
A friendly robotic sea turtle needs help. We add two piles of shiny shells together to get his map.
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
19
7
5
12
17
14
17
T
19
4
11
5
3
6
13
5
20
T
19
9
13
6
2
T
19
17
11
T
19
5
6
13
18
T
19
11 + 8 =T
3 + 1 =U
1 + 2 =D
3 + 2 =E
9 + 9 =I
2 + 4 =A
4 + 10 =B
4 + 7 =S
1 + 1 =W
8 + 4 =R
13 + 7 =F
6 + 11 =O
4 + 3 =H
6 + 3 =C
5 + 8 =L
0/15 letters found
Clue 3
Subtraction
Some rusty gears fell out of our bag. We subtract the lost gears to see how many are left.
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
1
3
B
1
B
1
10
18
16
2
8
12
7
13
10
10
7
8
16
5
15
5
13
16
B
1
8
4
19
3
18
8
7
8
18
4 - 3 =B
10 - 7 =U
10 - 3 =W
17 - 7 =L
9 - 4 =H
20 - 2 =Y
20 - 4 =S
14 - 2 =P
20 - 1 =G
3 - 1 =O
14 - 1 =I
17 - 2 =T
16 - 8 =A
9 - 5 =D
0/14 letters found
Clue 4
Skip counting
We follow a trail of footprints. We count them by twos to jump across the wet seaweed.
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
21
15
110
12
140
40
35
50
25
15
15
40
24
15
65
W
21
15
15
35
W
21
60
50
6
60
15
26
15
24
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27W
Skip-count by 10s. Fill the blank: 10, 20, 30, ___, 50, 60N
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75A
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45D
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, ___, 120, 130F
Skip-count by 5s. Fill the blank: 5, 10, ___, 20, 25E
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, ___, 55, 60G
Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10P
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, ___, 27, 30S
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, ___, 28, 30C
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35R
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16O
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160U
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, ___, 70, 80I
0/14 letters found
Clue 5
Missing addends — the last clue
We need ten fuel bolts to turn on the radar. We have seven. How many more do we need?
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
7 + ___ = 10
8 + ___ = 16
7 + ___ = 11
7 + ___ = 13
5 + ___ = 7
6 + ___ = 16
10 + ___ = 15
7 + ___ = 19
4 + ___ = 15
7 + ___ = 8
9 + ___ = 16
Step 2 — cross out the sentence with each answer
1.The villain blasts a trail with laser breath, then escapes through the floor with a mega drill.
2.The villain shatters the glass with a sonar scream, then traps the helpers with a glow net.
3.The villain shakes the ocean floor with a rocket stomp, then escapes through the floor with a mega drill.
4.The villain speeds away with a turbo tail-fin, then blocks the exits with a bubble shield.
5.The villain zaps the guards with an electric bite, then breaks the lock with a rust beam.
6.The villain shakes the ocean floor with a rocket stomp, then blinds the cameras with an oil splash.
7.The villain blasts a trail with laser breath, then blocks the exits with a bubble shield.
8.The villain zaps the guards with an electric bite, then blinds the cameras with an oil splash.
9.The villain shakes the ocean floor with a rocket stomp, then traps the helpers with a glow net.
10.The villain zaps the guards with an electric bite, then traps the helpers with a glow net.
11.The villain speeds away with a turbo tail-fin, then blinds the cameras with an oil splash.
12.The villain blasts a trail with laser breath, then traps the helpers with a glow net.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Cyber-Reef Caper
Culprit: Mega-Mouth (rocket stomp · glow net · left claw · seaweed wig · bubbly soap)
- Clue 1 (Place value): "THE VILLAIN DOES NOT USE THE RUST BEAM"What number has 7 tens and 1 one? = 71 (T) · What number has 3 tens and 4 ones? = 34 (S) · What number has 4 tens and 4 ones? = 44 (H) · What number has 3 tens and 5 ones? = 35 (A) · What number has 4 tens and 7 ones? = 47 (I) · What number has 4 tens and 1 one? = 41 (M) · What number has 9 tens and 2 ones? = 92 (L) · What number has 8 tens and 9 ones? = 89 (U) · What number has 9 tens and 8 ones? = 98 (B) · What number has 6 tens and 8 ones? = 68 (O) · What number has 3 tens and 3 ones? = 33 (D) · What number has 3 tens and 8 ones? = 38 (R) · What number has 1 ten and 3 ones? = 13 (N) · What number has 6 tens and 5 ones? = 65 (E) · What number has 8 tens and 8 ones? = 88 (V)
- Clue 2 (Addition): "THE ROBOT USED A LEFT CLAW TO STEAL IT"11 + 8 = 19 (T) · 3 + 1 = 4 (U) · 1 + 2 = 3 (D) · 3 + 2 = 5 (E) · 9 + 9 = 18 (I) · 2 + 4 = 6 (A) · 4 + 10 = 14 (B) · 4 + 7 = 11 (S) · 1 + 1 = 2 (W) · 8 + 4 = 12 (R) · 13 + 7 = 20 (F) · 6 + 11 = 17 (O) · 4 + 3 = 7 (H) · 6 + 3 = 9 (C) · 5 + 8 = 13 (L)
- Clue 3 (Subtraction): "BUBBLY SOAP WILL WASH THIS BAD GUY AWAY"4 - 3 = 1 (B) · 10 - 7 = 3 (U) · 10 - 3 = 7 (W) · 17 - 7 = 10 (L) · 9 - 4 = 5 (H) · 20 - 2 = 18 (Y) · 20 - 4 = 16 (S) · 14 - 2 = 12 (P) · 20 - 1 = 19 (G) · 3 - 1 = 2 (O) · 14 - 1 = 13 (I) · 17 - 2 = 15 (T) · 16 - 8 = 8 (A) · 9 - 5 = 4 (D)
- Clue 4 (Skip counting): "WE FOUND GREEN SEAWEED WIG PIECES"Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27 = 21 (W) · Skip-count by 10s. Fill the blank: 10, 20, 30, ___, 50, 60 = 40 (N) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75 = 65 (A) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45 = 35 (D) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, ___, 120, 130 = 110 (F) · Skip-count by 5s. Fill the blank: 5, 10, ___, 20, 25 = 15 (E) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, ___, 55, 60 = 50 (G) · Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10 = 6 (P) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, ___, 27, 30 = 24 (S) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, ___, 28, 30 = 26 (C) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35 = 25 (R) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16 = 12 (O) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160 = 140 (U) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, ___, 70, 80 = 60 (I)
- Clue 5 (Missing addends): surviving statement (box 9) → Mega-Mouth7 + ___ = 10 = 3 · 8 + ___ = 16 = 8 · 7 + ___ = 11 = 4 · 7 + ___ = 13 = 6 · 5 + ___ = 7 = 2 · 6 + ___ = 16 = 10 · 10 + ___ = 15 = 5 · 7 + ___ = 19 = 12 · 4 + ___ = 15 = 11 · 7 + ___ = 8 = 1 · 9 + ___ = 16 = 7
About this mystery
- Grade level
- Grade 1 math
- Math topics
- Place value, Addition, Subtraction, Skip counting, Missing addends
- Reading level
- grades 1-2
- Theme
- The Cyber-Reef Caper — set in The Cyber-Reef
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects