🔎 Ww2Grade 5Reading: grades 5-6AdditionSubtractionPlace valueFractions of a numberDivision
The Cipher Station Intruder
An elite intelligence base has been breached! A mysterious double agent has stolen the master codebook from the Chief Codebreaker. With the base on lockdown, we have compiled a list of suspect operatives. We must use logic and mathematical clues to identify the double agent before they can smuggle the secrets out of the station.
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 | Specialty | Gear | Writing Hand | Hair Evidence | Vulnerability |
|---|---|---|---|---|---|
| Odette Sansom | Radio Hacking | Micro Camera | Right Handed | Rusty Red Hair | Squeaky Floorboard |
| Gordon Welchman | Radio Hacking | Invisible Ink | Left Handed | Jet Black Hair | Squeaky Floorboard |
| Douglas MacArthur | Signal Intercept | Invisible Ink | Left Handed | Rusty Red Hair | Squeaky Floorboard |
| Alan Turing | Radio Hacking | Signal Flare | Left Handed | Sandy Blonde Hair | Squeaky Floorboard |
| George Patton | Code Cracking | Morse Clicker | Right Handed | Sandy Blonde Hair | Bright Spotlight |
| Winston Churchill | Radio Hacking | Micro Camera | Right Handed | Rusty Red Hair | Loud Siren |
| Virginia Hall | Map Forgery | Pocket Compass | Right Handed | Jet Black Hair | Squeaky Floorboard |
| Harry Truman | Signal Intercept | Morse Clicker | Right Handed | Sandy Blonde Hair | Squeaky Floorboard |
| Guy Gibson | Night Flying | Signal Flare | Right Handed | Sandy Blonde Hair | Bright Spotlight |
| Violette Szabo | Radio Hacking | Signal Flare | Right Handed | Jet Black Hair | Bright Spotlight |
| James Doolittle | Signal Intercept | Invisible Ink | Right Handed | Rusty Red Hair | Squeaky Floorboard |
| George Marshall | Night Flying | Micro Camera | Left Handed | Jet Black Hair | Loud Siren |
| Nancy Wake | Night Flying | Signal Flare | Right Handed | Jet Black Hair | Bright Spotlight |
| Joan Clarke | Night Flying | Pocket Compass | Right Handed | Rusty Red Hair | Squeaky Floorboard |
| Eleanor Roosevelt | Night Flying | Morse Clicker | Left Handed | Rusty Red Hair | Loud Siren |
| Mavis Batey | Radio Hacking | Pocket Compass | Right Handed | Rusty Red Hair | Squeaky Floorboard |
| Bernard Montgomery | Night Flying | Pocket Compass | Right Handed | Rusty Red Hair | Bright Spotlight |
| Tommy Flowers | Radio Hacking | Morse Clicker | Right Handed | Rusty Red Hair | Squeaky Floorboard |
| Richard Sorge | Night Flying | Morse Clicker | Left Handed | Rusty Red Hair | Bright Spotlight |
| Omar Bradley | Night Flying | Invisible Ink | Right Handed | Rusty Red Hair | Bright Spotlight |
| Matthew Ridgway | Map Forgery | Morse Clicker | Right Handed | Jet Black Hair | Loud Siren |
Clue 1
Addition
We counted the extra codebooks and spare radio tubes in the supply room to find our first clue. Add up the total supplies to reveal the agent's 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
6771
5264
2865
3667
7240
6903
9488
7357
2865
6385
9698
2865
3708
T
6771
3667
7240
2865
3225
3708
7240
T
6771
6903
3225
2865
6385
6446
5717
6937
4512
7240
6937
6385
6446
2865
4512
6385
2716 + 4055 =T
4340 + 2106 =M
2789 + 1723 =R
2368 + 2896 =H
2535 + 1173 =N
4574 + 5124 =G
2376 + 1291 =D
2454 + 3931 =A
2750 + 4153 =U
1454 + 1411 =E
2725 + 2992 =I
3891 + 3466 =L
2918 + 6570 =B
1645 + 1580 =S
3204 + 4036 =O
3169 + 3768 =C
0/16 letters found
Clue 2
Subtraction
The telegraph operator compared the number of sent messages against the incoming wire logs. Find the difference between these tallies to reveal the writing hand of the intruder.
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
5986
6513
7690
4751
4106
T
5986
8927
4702
7165
7690
8927
6017
4751
8963
4106
7690
7165
T
5986
6513
7690
5009
7690
7165
8963
7690
8927
8927
4751
8963
6513
T
5986
6513
3698
4106
7165
7690
7165
7359 - 1373 =T
6089 - 1080 =L
10355 - 1392 =G
13573 - 4646 =R
11543 - 4378 =D
7832 - 1815 =S
12551 - 4861 =E
11230 - 4717 =H
5950 - 1844 =N
6646 - 1895 =I
4411 - 713 =A
9576 - 4874 =U
0/12 letters found
Clue 3
Place value
A dial on the high-frequency radar receiver is stuck on a specific number. Look at the value of the digit in the hundreds place to discover the intruder's hair color.
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
60
3000
500
30
20
A
60
1000
4000
7000
50
200
200
80
70
200
A
60
80
2000
3000
700
A
60
80
20
2000
100
300
20
600
400
50
50
A
60
400
6000
A
60
90
A
60
4000
What is the value of the 6 in 548,768?A
What is the value of the 9 in 25,891?W
What is the value of the 7 in 206,718?C
What is the value of the 1 in 827,137?T
What is the value of the 5 in 81,859?L
What is the value of the 3 in 40,632?U
What is the value of the 2 in 12,130?D
What is the value of the 4 in 54,651?Y
What is the value of the 2 in 874,216?O
What is the value of the 5 in 304,572?Q
What is the value of the 6 in 26,398?N
What is the value of the 7 in 44,975?B
What is the value of the 7 in 87,390?F
What is the value of the 3 in 83,148?S
What is the value of the 4 in 88,458?I
What is the value of the 8 in 702,383?R
What is the value of the 2 in 91,626?E
What is the value of the 6 in 48,654?V
What is the value of the 3 in 71,386?H
What is the value of the 1 in 931,985?K
0/20 letters found
Clue 4
Fractions of a number
Our courier recovered a bundle of classified files, but some are damaged by water. Calculate the fraction of readable files to pinpoint the suspect's vulnerability.
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
40
5
6
34
14
2
14
34
28
T
40
14
T
40
9
20
13
18
5
14
9
34
5
14
2
34
15
28
T
40
19
34
6
2
5
14
9
34
5/8 of 64 =T
2/6 of 102 =R
1/10 of 130 =N
2/6 of 57 =Y
5/6 of 24 =O
4/8 of 30 =U
1/6 of 84 =A
1/10 of 50 =H
3/6 of 18 =I
4/8 of 36 =C
4/6 of 42 =S
5/10 of 4 =D
1/10 of 60 =E
0/13 letters found
Clue 5
Division facts (1-12) — the last clue
The generator must be shared among several sectors of the bunker. Divide the spare electricity units evenly among the stations to unlock the final piece of the puzzle.
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
40 ÷ 8 = ?
50 ÷ 5 = ?
32 ÷ 4 = ?
63 ÷ 9 = ?
18 ÷ 6 = ?
144 ÷ 12 = ?
54 ÷ 9 = ?
5 ÷ 5 = ?
28 ÷ 7 = ?
22 ÷ 11 = ?
90 ÷ 10 = ?
Step 2 — cross out the sentence with each answer
1.The villain flew the scout plane, then hid a pocket spy camera.
2.The villain hacked the wireless transmitter, then sabotaged the engine gears.
3.The villain cracked the encrypted codes, then escaped into the dark night.
4.The villain forged the invasion map, then hid a pocket spy camera.
5.The villain forged the invasion map, then sabotaged the engine gears.
6.The villain hacked the wireless transmitter, then stole the secret blueprints.
7.The villain flew the scout plane, then sabotaged the engine gears.
8.The villain cracked the encrypted codes, then stole the secret blueprints.
9.The villain cracked the encrypted codes, then sabotaged the engine gears.
10.The villain hacked the wireless transmitter, then escaped into the dark night.
11.The villain forged the invasion map, then stole the secret blueprints.
12.The villain hacked the wireless transmitter, then scrambled the radar array.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Cipher Station Intruder
Culprit: Mavis Batey (Radio Hacking · Pocket Compass · Right Handed · Rusty Red Hair · Squeaky Floorboard)
- Clue 1 (Addition): "THE DOUBLE AGENT DOES NOT USE A MICRO CAMERA"2716 + 4055 = 6771 (T) · 4340 + 2106 = 6446 (M) · 2789 + 1723 = 4512 (R) · 2368 + 2896 = 5264 (H) · 2535 + 1173 = 3708 (N) · 4574 + 5124 = 9698 (G) · 2376 + 1291 = 3667 (D) · 2454 + 3931 = 6385 (A) · 2750 + 4153 = 6903 (U) · 1454 + 1411 = 2865 (E) · 2725 + 2992 = 5717 (I) · 3891 + 3466 = 7357 (L) · 2918 + 6570 = 9488 (B) · 1645 + 1580 = 3225 (S) · 3204 + 4036 = 7240 (O) · 3169 + 3768 = 6937 (C)
- Clue 2 (Subtraction): "THE INTRUDER SIGNED THE LEDGER RIGHT HANDED"7359 - 1373 = 5986 (T) · 6089 - 1080 = 5009 (L) · 10355 - 1392 = 8963 (G) · 13573 - 4646 = 8927 (R) · 11543 - 4378 = 7165 (D) · 7832 - 1815 = 6017 (S) · 12551 - 4861 = 7690 (E) · 11230 - 4717 = 6513 (H) · 5950 - 1844 = 4106 (N) · 6646 - 1895 = 4751 (I) · 4411 - 713 = 3698 (A) · 9576 - 4874 = 4702 (U)
- Clue 3 (Place value): "A SQUEAKY FLOORBOARD SCARED THE VILLAIN AWAY"What is the value of the 6 in 548,768? = 60 (A) · What is the value of the 9 in 25,891? = 90 (W) · What is the value of the 7 in 206,718? = 700 (C) · What is the value of the 1 in 827,137? = 100 (T) · What is the value of the 5 in 81,859? = 50 (L) · What is the value of the 3 in 40,632? = 30 (U) · What is the value of the 2 in 12,130? = 2000 (D) · What is the value of the 4 in 54,651? = 4000 (Y) · What is the value of the 2 in 874,216? = 200 (O) · What is the value of the 5 in 304,572? = 500 (Q) · What is the value of the 6 in 26,398? = 6000 (N) · What is the value of the 7 in 44,975? = 70 (B) · What is the value of the 7 in 87,390? = 7000 (F) · What is the value of the 3 in 83,148? = 3000 (S) · What is the value of the 4 in 88,458? = 400 (I) · What is the value of the 8 in 702,383? = 80 (R) · What is the value of the 2 in 91,626? = 20 (E) · What is the value of the 6 in 48,654? = 600 (V) · What is the value of the 3 in 71,386? = 300 (H) · What is the value of the 1 in 931,985? = 1000 (K)
- Clue 4 (Fractions of a number): "THE RADAR STATION CHAIR HAD RUSTY RED HAIR"5/8 of 64 = 40 (T) · 2/6 of 102 = 34 (R) · 1/10 of 130 = 13 (N) · 2/6 of 57 = 19 (Y) · 5/6 of 24 = 20 (O) · 4/8 of 30 = 15 (U) · 1/6 of 84 = 14 (A) · 1/10 of 50 = 5 (H) · 3/6 of 18 = 9 (I) · 4/8 of 36 = 18 (C) · 4/6 of 42 = 28 (S) · 5/10 of 4 = 2 (D) · 1/10 of 60 = 6 (E)
- Clue 5 (Division facts (1-12)): surviving statement (box 11) → Mavis Batey40 ÷ 8 = 5 · 50 ÷ 5 = 10 · 32 ÷ 4 = 8 · 63 ÷ 9 = 7 · 18 ÷ 6 = 3 · 144 ÷ 12 = 12 · 54 ÷ 9 = 6 · 5 ÷ 5 = 1 · 28 ÷ 7 = 4 · 22 ÷ 11 = 2 · 90 ÷ 10 = 9
About this mystery
- Grade level
- Grade 5 math
- Math topics
- Addition, Subtraction, Place value, Fractions of a number, Division
- Reading level
- grades 5-6
- Theme
- The Cipher Station Intruder — set in Bletchley Park Codebreaking Headquarters
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects