🔎 Stranger ThingsGrade 5Reading: grades 3-4MultiplicationFractions of a numberOrder of operationsRoundingDivision
The Mystery of the Shadow Signal
A strange radio signal hijacked the town broadcasting tower! The Hawkins AV Club needs your detective skills to decode the math clues, eliminate suspects, and track down the 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 | Special Gadget | Signal Boost | Watch Wrist | Cap Color | Disruption Tool |
|---|---|---|---|---|---|
| Bob Sinclair | Proximity Radar | Neon Pulse | Left Handed Watch | Blue Cap | Loud Alarm |
| Argyle Smith | Proximity Radar | Neon Pulse | Right Handed Watch | Yellow Cap | Bright Flash |
| Murray Bauman | Proximity Radar | Static Blast | Right Handed Watch | Yellow Cap | Bright Flash |
| Jim Harrington | Walkie Talkie | Laser Beam | Right Handed Watch | Red Cap | Bright Flash |
| Holly Wheeler | Cassette Player | Radar Jam | Left Handed Watch | Red Cap | Bright Flash |
| Chrissy Cunningham | Walkie Talkie | Static Blast | Right Handed Watch | Red Cap | Tuning Fork |
| Lucas Drake | Walkie Talkie | Neon Pulse | Right Handed Watch | Yellow Cap | Bright Flash |
| Ted Wheeler | Cassette Player | Echo Surge | Right Handed Watch | Blue Cap | Bright Flash |
| Robin Hayes | Cassette Player | Radar Jam | Right Handed Watch | Blue Cap | Bright Flash |
| Patrick McKinney | Arcade Decoder | Neon Pulse | Left Handed Watch | Blue Cap | Loud Alarm |
| Joyce Wheeler | Cassette Player | Static Blast | Right Handed Watch | Red Cap | Loud Alarm |
| Erika Sinclair | Flashlight Array | Laser Beam | Left Handed Watch | Yellow Cap | Bright Flash |
| Tommy Flynn | Arcade Decoder | Neon Pulse | Right Handed Watch | Blue Cap | Bright Flash |
| Will Henderson | Arcade Decoder | Neon Pulse | Right Handed Watch | Blue Cap | Loud Alarm |
| Fred Benson | Walkie Talkie | Echo Surge | Left Handed Watch | Blue Cap | Bright Flash |
| Barb Holland | Walkie Talkie | Neon Pulse | Left Handed Watch | Blue Cap | Tuning Fork |
| Max Vance | Cassette Player | Static Blast | Right Handed Watch | Blue Cap | Tuning Fork |
| Karen Wheeler | Walkie Talkie | Echo Surge | Right Handed Watch | Blue Cap | Loud Alarm |
| Nancy Vance | Walkie Talkie | Static Blast | Left Handed Watch | Blue Cap | Bright Flash |
| Jason Carver | Walkie Talkie | Laser Beam | Right Handed Watch | Blue Cap | Bright Flash |
| Jane Hopper | Cassette Player | Laser Beam | Right Handed Watch | Blue Cap | Bright Flash |
Clue 1
Multiplication facts (1-12)
You find box loads of radio parts stacked in neat grid rows. Multiply to tally the total gear.
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
45
56
35
20
21
16
16
54
21
84
108
14
35
27
84
14
T
45
25
27
35
5
54
108
54
5
1
54
50
9 × 5 =T
4 × 4 =L
12 × 9 =D
9 × 6 =A
7 × 2 =O
5 × 5 =U
9 × 3 =S
1 × 1 =J
10 × 2 =V
8 × 7 =H
5 × 1 =R
5 × 7 =E
3 × 7 =I
10 × 5 =M
7 × 12 =N
0/15 letters found
Clue 2
Fractions of a number
The AV Club logs show that only a fraction of the radio towers are sending fake signals.
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
38
10
35
18
23
34
34
34
16
W
38
16
W
38
16
35
14
7
15
18
35
7
23
21
10
28
7
35
W
38
21
10
34
35
5/10 of 76 =W
3/6 of 36 =N
1/2 of 42 =R
3/6 of 14 =H
5/8 of 16 =I
1/5 of 170 =S
8/10 of 20 =A
2/6 of 105 =T
2/10 of 75 =O
1/5 of 115 =E
1/5 of 70 =C
7/10 of 40 =G
0/12 letters found
Clue 3
Order of operations
To unlock the control console, you must solve this multi-step code sequence in correct order.
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
41
59
29
19
36
36
63
19
74
7
63
18
11
36
19
74
70
59
70
11
76
63
11
60
19
79
41
T
28
53
36
63
18
41
3 × 12 - 8 =T
7 × 8 - 27 =V
12 × 3 - 17 =I
8 × 12 - 20 =Y
1 + 3 × 2 =W
20 + 5 × 8 =R
5 × 12 - 7 =F
39 + 8 × 3 =A
24 + 2 × 6 =L
10 + 7 × 7 =E
7 × 4 - 10 =S
67 + 4 × 3 =G
6 + 5 × 7 =H
7 × 11 - 7 =D
2 + 3 × 3 =B
68 + 2 × 3 =N
0/16 letters found
Clue 4
Rounding
The lab radar monitor only shows rounded frequencies to the nearest hundred.
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
20
1300
2900
1100
110
900
A
20
7000
430
A
20
370
230
9000
290
7000
7000
110
230
A
20
170
170
70
110
370
900
110
130
110
Round 19 to the nearest tenA
Round 107 to the nearest tenE
Round 374 to the nearest tenS
Round 929 to the nearest hundredC
Round 2,852 to the nearest hundredL
Round 127 to the nearest tenN
Round 432 to the nearest tenW
Round 9,170 to the nearest thousandR
Round 173 to the nearest tenT
Round 73 to the nearest tenH
Round 226 to the nearest tenD
Round 293 to the nearest tenO
Round 1,081 to the nearest hundredU
Round 1,314 to the nearest hundredB
Round 7,356 to the nearest thousandP
0/15 letters found
Clue 5
Division facts (1-12) — the last clue
Divide the remaining walkie talkie channels equally among the team to isolate the culprit.
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
22 ÷ 11 = ?
11 ÷ 1 = ?
18 ÷ 2 = ?
40 ÷ 10 = ?
24 ÷ 4 = ?
21 ÷ 7 = ?
96 ÷ 12 = ?
42 ÷ 6 = ?
5 ÷ 1 = ?
144 ÷ 12 = ?
100 ÷ 10 = ?
Step 2 — cross out the sentence with each answer
1.The villain cranked the cassette player, then triggered an echo surge.
2.The villain cranked the cassette player, then shot a laser beam.
3.The villain scanned with the proximity radar, then shot a laser beam.
4.The villain cracked the arcade decoder, then triggered an echo surge.
5.The villain switched on the walkie talkie, then unleashed a static blast.
6.The villain flashed the flashlight array, then fired a neon pulse.
7.The villain scanned with the proximity radar, then fired a neon pulse.
8.The villain flashed the flashlight array, then shot a laser beam.
9.The villain switched on the walkie talkie, then shot a laser beam.
10.The villain flashed the flashlight array, then triggered an echo surge.
11.The villain cracked the arcade decoder, then fired a neon pulse.
12.The villain scanned with the proximity radar, then activated the radar jam.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Mystery of the Shadow Signal
Culprit: Ted Wheeler (Cassette Player · Echo Surge · Right Handed Watch · Blue Cap · Bright Flash)
- Clue 1 (Multiplication facts (1-12)): "THE VILLAIN DOES NOT USE RADAR JAM"9 × 5 = 45 (T) · 4 × 4 = 16 (L) · 12 × 9 = 108 (D) · 9 × 6 = 54 (A) · 7 × 2 = 14 (O) · 5 × 5 = 25 (U) · 9 × 3 = 27 (S) · 1 × 1 = 1 (J) · 10 × 2 = 20 (V) · 8 × 7 = 56 (H) · 5 × 1 = 5 (R) · 5 × 7 = 35 (E) · 3 × 7 = 21 (I) · 10 × 5 = 50 (M) · 7 × 12 = 84 (N)
- Clue 2 (Fractions of a number): "WITNESS SAW A WATCH ON THE RIGHT WRIST"5/10 of 76 = 38 (W) · 3/6 of 36 = 18 (N) · 1/2 of 42 = 21 (R) · 3/6 of 14 = 7 (H) · 5/8 of 16 = 10 (I) · 1/5 of 170 = 34 (S) · 8/10 of 20 = 16 (A) · 2/6 of 105 = 35 (T) · 2/10 of 75 = 15 (O) · 1/5 of 115 = 23 (E) · 1/5 of 70 = 14 (C) · 7/10 of 40 = 28 (G)
- Clue 3 (Order of operations): "THE VILLAIN WAS BLINDED BY A BRIGHT FLASH"3 × 12 - 8 = 28 (T) · 7 × 8 - 27 = 29 (V) · 12 × 3 - 17 = 19 (I) · 8 × 12 - 20 = 76 (Y) · 1 + 3 × 2 = 7 (W) · 20 + 5 × 8 = 60 (R) · 5 × 12 - 7 = 53 (F) · 39 + 8 × 3 = 63 (A) · 24 + 2 × 6 = 36 (L) · 10 + 7 × 7 = 59 (E) · 7 × 4 - 10 = 18 (S) · 67 + 4 × 3 = 79 (G) · 6 + 5 × 7 = 41 (H) · 7 × 11 - 7 = 70 (D) · 2 + 3 × 3 = 11 (B) · 68 + 2 × 3 = 74 (N)
- Clue 4 (Rounding): "A BLUE CAP WAS DROPPED AT THE SCENE"Round 19 to the nearest ten = 20 (A) · Round 107 to the nearest ten = 110 (E) · Round 374 to the nearest ten = 370 (S) · Round 929 to the nearest hundred = 900 (C) · Round 2,852 to the nearest hundred = 2900 (L) · Round 127 to the nearest ten = 130 (N) · Round 432 to the nearest ten = 430 (W) · Round 9,170 to the nearest thousand = 9000 (R) · Round 173 to the nearest ten = 170 (T) · Round 73 to the nearest ten = 70 (H) · Round 226 to the nearest ten = 230 (D) · Round 293 to the nearest ten = 290 (O) · Round 1,081 to the nearest hundred = 1100 (U) · Round 1,314 to the nearest hundred = 1300 (B) · Round 7,356 to the nearest thousand = 7000 (P)
- Clue 5 (Division facts (1-12)): surviving statement (box 1) → Ted Wheeler22 ÷ 11 = 2 · 11 ÷ 1 = 11 · 18 ÷ 2 = 9 · 40 ÷ 10 = 4 · 24 ÷ 4 = 6 · 21 ÷ 7 = 3 · 96 ÷ 12 = 8 · 42 ÷ 6 = 7 · 5 ÷ 1 = 5 · 144 ÷ 12 = 12 · 100 ÷ 10 = 10
About this mystery
- Grade level
- Grade 5 math
- Math topics
- Multiplication, Fractions of a number, Order of operations, Rounding, Division
- Reading level
- grades 3-4
- Theme
- The Mystery of the Shadow Signal — set in Hawkins AV Club Station
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects