Grade 2Reading: grades 3-4AdditionSubtractionWord problemsSkip countingMissing addends
The Mystery of the Sunken Sub
Someone snuck into the underwater vault and took the ancient sea map! Solve the clues to catch the suspect before they sail away.
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 | Primary Tool | Secondary Gear | Dominant Hand | Helmet Color | Vulnerability |
|---|---|---|---|---|---|
| Pearl Pete | sonar blaster | deep lamp | right handed | neon blue helmet | sticky sea kelp |
| Piper Port | sonar blaster | deep lamp | left handed | bright yellow helmet | loud horn |
| Officer Finn | bubble net | deep lamp | right handed | neon blue helmet | flashing beacon |
| Anchor Andy | aqua jet | signal flare | left handed | bright yellow helmet | loud horn |
| Splash Spencer | sonar blaster | signal flare | right handed | neon blue helmet | flashing beacon |
| Harbor Hank | aqua jet | current booster | right handed | bright yellow helmet | loud horn |
| Sailor Sally | aqua jet | anchor drop | left handed | bright yellow helmet | flashing beacon |
| Diver Dan | bubble net | turbo propeller | right handed | bright yellow helmet | flashing beacon |
| Reef Riley | aqua jet | anchor drop | right handed | bright yellow helmet | loud horn |
| Captain Cal | aqua jet | current booster | right handed | dark green helmet | flashing beacon |
| Current Clara | aqua jet | turbo propeller | left handed | dark green helmet | loud horn |
| Captain Jack | sonar blaster | anchor drop | right handed | neon blue helmet | loud horn |
| Sailor Sam | bubble net | anchor drop | left handed | bright yellow helmet | loud horn |
| Submarine Seth | bubble net | current booster | right handed | neon blue helmet | sticky sea kelp |
| Beacon Bella | grapple hook | signal flare | left handed | neon blue helmet | sticky sea kelp |
| Coastline Chloe | aqua jet | current booster | left handed | neon blue helmet | loud horn |
| Shellie Shore | aqua jet | turbo propeller | left handed | bright yellow helmet | loud horn |
| Coral Cody | aqua jet | signal flare | right handed | dark green helmet | flashing beacon |
| Barnaby Bay | bubble net | turbo propeller | left handed | bright yellow helmet | loud horn |
| Tides Tim | sonar blaster | signal flare | left handed | neon blue helmet | flashing beacon |
| Trench Tess | grapple hook | anchor drop | right handed | neon blue helmet | sticky sea kelp |
Clue 1
Addition
We counted the supply crates packed on the boat deck to find our first 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
35
26
65
85
49
67
23
66
44
T
35
93
24
65
48
80
24
T
35
49
48
65
96
93
65
65
23
67
96
95
23
19 + 16 =T
21 + 23 =I
47 + 33 =N
28 + 57 =C
15 + 34 =U
43 + 22 =E
38 + 29 =L
16 + 10 =H
61 + 34 =M
30 + 36 =R
24 + 24 =S
15 + 8 =P
10 + 14 =O
30 + 66 =A
43 + 50 =D
0/15 letters found
Clue 2
Subtraction
Some oxygen tanks were taken from the shed so we subtracted to see what was 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.
W
41
71
33
42
67
21
21
67
21
21
73
W
41
73
38
67
36
33
78
73
42
39
67
39
39
71
31
67
63
51 - 10 =W
57 - 15 =N
40 - 4 =F
65 - 26 =D
99 - 32 =E
52 - 14 =L
66 - 35 =V
51 - 30 =S
108 - 37 =I
45 - 12 =T
98 - 20 =H
85 - 22 =R
105 - 32 =A
0/13 letters found
Clue 3
Word problems
The harbor master gave us a report about missing diving tools to solve.
Solve each problem to learn its letter, then write the letters in the boxes to fill in the missing word.
Someonescaredthevillainoffwith.
L
22
37
12
20
15
37
6
27
Junior Diver lined up 2 rows of 11 air tanks. How many air tanks in all?L
Junior Diver found 2 air tanks yesterday and 35 more today. How many air tanks in all?O
Junior Diver found 8 compasses yesterday and 7 more today. How many compasses in all?H
Junior Diver lined up 3 rows of 9 sea maps. How many sea maps in all?N
Junior Diver lined up 3 rows of 2 dive fins. How many dive fins in all?R
Junior Diver lined up 4 rows of 3 sea maps. How many sea maps in all?U
Junior Diver lined up 5 rows of 4 glow sticks. How many glow sticks in all?D
0/7 letters found
Clue 4
Skip counting
We counted the sonar pings coming from the bay in steady jumps.
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
33
100
22
50
130
25
6
30
39
90
90
27
16
25
39
90
36
39
6
45
50
9
27
22
16
A
33
9
14
22
27
60
60
39
14
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ___, 36, 39A
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, ___, 55, 60I
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55V
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, ___, 140, 150G
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, ___, 39, 42M
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, ___, 18, 20W
Skip-count by 10s. Fill the blank: 10, 20, ___, 40, 50Y
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45E
Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10T
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, ___, 65, 70P
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110L
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, ___, 16, 18D
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, 21, 24, ___, 30, 33O
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, ___, 24, 26R
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, ___, 110, 120B
Skip-count by 3s. Fill the blank: 3, 6, ___, 12, 15S
0/17 letters found
Clue 5
Missing addends — the last clue
We knew how many map pieces we needed and figured out what was 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
10 + ___ = 11
1 + ___ = 5
8 + ___ = 17
6 + ___ = 9
3 + ___ = 9
4 + ___ = 9
8 + ___ = 20
10 + ___ = 20
3 + ___ = 14
4 + ___ = 6
7 + ___ = 14
Step 2 — cross out the sentence with each answer
1.The villain trapped the gate in a bubble net, then lowered the anchor drop.
2.The villain sliced through with the laser cutter, then lowered the anchor drop.
3.The villain latched on using the grapple hook, then spun the turbo propeller.
4.The villain zoomed off with the aqua jet, then spun the turbo propeller.
5.The villain sliced through with the laser cutter, then switched on the deep lamp.
6.The villain latched on using the grapple hook, then switched on the deep lamp.
7.The villain sliced through with the laser cutter, then lit a signal flare.
8.The villain trapped the gate in a bubble net, then spun the turbo propeller.
9.The villain zoomed off with the aqua jet, then lit a signal flare.
10.The villain zoomed off with the aqua jet, then lowered the anchor drop.
11.The villain zoomed off with the aqua jet, then switched on the deep lamp.
12.The villain fired the sonar blaster, then fired the current booster.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Mystery of the Sunken Sub
Culprit: Barnaby Bay (bubble net · turbo propeller · left handed · bright yellow helmet · loud horn)
- Clue 1 (Addition): "THE CULPRIT DOES NOT USE A DEEP LAMP"19 + 16 = 35 (T) · 21 + 23 = 44 (I) · 47 + 33 = 80 (N) · 28 + 57 = 85 (C) · 15 + 34 = 49 (U) · 43 + 22 = 65 (E) · 38 + 29 = 67 (L) · 16 + 10 = 26 (H) · 61 + 34 = 95 (M) · 30 + 36 = 66 (R) · 24 + 24 = 48 (S) · 15 + 8 = 23 (P) · 10 + 14 = 24 (O) · 30 + 66 = 96 (A) · 43 + 50 = 93 (D)
- Clue 2 (Subtraction): "WITNESSES SAW A LEFT HANDED DIVER"51 - 10 = 41 (W) · 57 - 15 = 42 (N) · 40 - 4 = 36 (F) · 65 - 26 = 39 (D) · 99 - 32 = 67 (E) · 52 - 14 = 38 (L) · 66 - 35 = 31 (V) · 51 - 30 = 21 (S) · 108 - 37 = 71 (I) · 45 - 12 = 33 (T) · 98 - 20 = 78 (H) · 85 - 22 = 63 (R) · 105 - 32 = 73 (A)
- Clue 3 (Word problems): "LOUD HORN"Junior Diver lined up 2 rows of 11 air tanks. How many air tanks in all? = 22 (L) · Junior Diver found 2 air tanks yesterday and 35 more today. How many air tanks in all? = 37 (O) · Junior Diver found 8 compasses yesterday and 7 more today. How many compasses in all? = 15 (H) · Junior Diver lined up 3 rows of 9 sea maps. How many sea maps in all? = 27 (N) · Junior Diver lined up 3 rows of 2 dive fins. How many dive fins in all? = 6 (R) · Junior Diver lined up 4 rows of 3 sea maps. How many sea maps in all? = 12 (U) · Junior Diver lined up 5 rows of 4 glow sticks. How many glow sticks in all? = 20 (D)
- Clue 4 (Skip counting): "A BRIGHT YELLOW HELMET VISOR WAS DROPPED"Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ___, 36, 39 = 33 (A) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, ___, 55, 60 = 50 (I) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55 = 45 (V) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, ___, 140, 150 = 130 (G) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, ___, 39, 42 = 36 (M) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, ___, 18, 20 = 16 (W) · Skip-count by 10s. Fill the blank: 10, 20, ___, 40, 50 = 30 (Y) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45 = 39 (E) · Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10 = 6 (T) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, ___, 65, 70 = 60 (P) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110 = 90 (L) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, ___, 16, 18 = 14 (D) · 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, 21, 24, ___, 30, 33 = 27 (O) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, ___, 24, 26 = 22 (R) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, ___, 110, 120 = 100 (B) · Skip-count by 3s. Fill the blank: 3, 6, ___, 12, 15 = 9 (S)
- Clue 5 (Missing addends): surviving statement (box 8) → Barnaby Bay10 + ___ = 11 = 1 · 1 + ___ = 5 = 4 · 8 + ___ = 17 = 9 · 6 + ___ = 9 = 3 · 3 + ___ = 9 = 6 · 4 + ___ = 9 = 5 · 8 + ___ = 20 = 12 · 10 + ___ = 20 = 10 · 3 + ___ = 14 = 11 · 4 + ___ = 6 = 2 · 7 + ___ = 14 = 7
About this mystery
- Grade level
- Grade 2 math
- Math topics
- Addition, Subtraction, Word problems, Skip counting, Missing addends
- Reading level
- grades 3-4
- Theme
- The Mystery of the Sunken Sub — set in Coral Cove Naval Station
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects