🔎 MathGrade 5Reading: grades 5-6Fractions of a numberOrder of operationsMultiplicationRoundingDivision
The Case of the Miscalculated Mastermind
The Golden Slide Rule has been stolen from the central vault at the National Academy of Mathematics! The culprit left behind a series of math clues at the scene. Crack the codes and help Detective Vector identify the thief before they divide and conquer!
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 | Math Specialty | Gadget Power | Nervous Habit | Hair Style | Math Flaw |
|---|---|---|---|---|---|
| Rene Descartes | Calculus Beam | Pi Sphere | Clicking a Stopwatch | Sleek Ruler Straight | Unsimplified Fractions |
| Fibonacci | Calculus Beam | Pi Sphere | Clicking a Stopwatch | Curly Ink Black | Division by Zero |
| Gottfried Leibniz | Calculus Beam | Prime Barrier | Tapping a Pencil | Spiky Chalk White | Unsimplified Fractions |
| George Boole | Fractal Blast | Prime Barrier | Tapping a Pencil | Curly Ink Black | Unsimplified Fractions |
| Grace Hopper | Matrix Shift | Binary Spike | Clicking a Stopwatch | Sleek Ruler Straight | Unsimplified Fractions |
| John von Neumann | Calculus Beam | Pi Sphere | Tapping a Pencil | Curly Ink Black | Negative Numbers |
| Paul Erdos | Calculus Beam | Binary Spike | Clicking a Stopwatch | Curly Ink Black | Division by Zero |
| Sophie Germain | Geometry Shield | Pi Sphere | Clicking a Stopwatch | Sleek Ruler Straight | Negative Numbers |
| Florence Nightingale | Calculus Beam | Binary Spike | Tapping a Pencil | Curly Ink Black | Division by Zero |
| Emmy Noether | Matrix Shift | Graph Pulse | Tapping a Pencil | Spiky Chalk White | Division by Zero |
| Carl Gauss | Matrix Shift | Prime Barrier | Tapping a Pencil | Sleek Ruler Straight | Unsimplified Fractions |
| Katherine Johnson | Fractal Blast | Graph Pulse | Tapping a Pencil | Curly Ink Black | Division by Zero |
| Srinivasa Ramanujan | Fractal Blast | Logarithm Trap | Clicking a Stopwatch | Spiky Chalk White | Negative Numbers |
| Maryam Mirzakhani | Calculus Beam | Prime Barrier | Tapping a Pencil | Sleek Ruler Straight | Division by Zero |
| Euclid | Geometry Shield | Logarithm Trap | Tapping a Pencil | Spiky Chalk White | Negative Numbers |
| Leonhard Euler | Geometry Shield | Logarithm Trap | Tapping a Pencil | Curly Ink Black | Division by Zero |
| Hypatia | Fractal Blast | Binary Spike | Tapping a Pencil | Curly Ink Black | Division by Zero |
| Pythagoras | Vector Dash | Prime Barrier | Tapping a Pencil | Curly Ink Black | Unsimplified Fractions |
| Benoit Mandelbrot | Calculus Beam | Logarithm Trap | Tapping a Pencil | Spiky Chalk White | Division by Zero |
| Isaac Newton | Calculus Beam | Prime Barrier | Tapping a Pencil | Spiky Chalk White | Negative Numbers |
| Blaise Pascal | Matrix Shift | Graph Pulse | Tapping a Pencil | Curly Ink Black | Division by Zero |
Clue 1
Fractions of a number
We analyzed the laser grid on the vault door where only a specific fraction of the security beams were activated.
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
23
29
11
18
39
33
33
40
39
21
27
3
11
4
21
3
T
23
35
4
11
33
3
14
40
9
39
T
23
29
31
T
23
9
40
36
1/2 of 46 =T
3/6 of 66 =L
2/6 of 108 =P
1/5 of 145 =H
2/4 of 36 =V
3/5 of 45 =D
1/3 of 117 =I
3/6 of 6 =O
1/6 of 66 =E
2/4 of 62 =M
1/3 of 120 =A
1/10 of 40 =S
2/8 of 56 =G
1/5 of 45 =R
2/10 of 175 =U
2/4 of 42 =N
0/16 letters found
Clue 2
Order of operations
decrypting the locked computer terminal required evaluating the mathematical operations in their exact 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
73
48
32
7
66
7
51
32
9
T
73
63
22
7
7
32
32
29
T
73
22
51
51
13
29
34
22
51
32
29
9
13
69
12 × 7 - 11 =T
10 × 9 - 24 =U
6 × 3 - 11 =S
53 + 4 × 4 =L
12 × 4 - 16 =E
9 × 9 - 18 =W
7 × 5 - 26 =C
11 × 7 - 29 =H
5 × 11 - 26 =N
9 × 5 - 23 =A
12 × 6 - 21 =P
6 × 6 - 23 =I
10 + 3 × 8 =G
0/13 letters found
Clue 3
Multiplication facts (1-12)
Examining the grid of footprints near the display case revealed equal rows of identical boot prints.
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
22
40
64
56
108
132
132
24
108
80
14
24
70
70
T
22
2
84
84
64
7
54
12
7
108
56
108
70
108
2
80
54
12
33
64
48
2
11 × 2 =T
12 × 7 =P
8 × 5 =H
12 × 1 =Y
6 × 4 =A
8 × 8 =E
6 × 9 =B
7 × 2 =W
7 × 10 =S
11 × 12 =L
7 × 1 =D
8 × 6 =R
9 × 12 =I
10 × 8 =N
11 × 3 =Z
7 × 8 =V
2 × 1 =O
0/17 letters found
Clue 4
Rounding
The energy sensor readout at the crime scene logged power spikes rounded to the nearest hundred units.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
C
230
2300
700
50
30
5000
3700
20
2000
50
200
C
230
20
370
200
5000
700
4300
200
170
3000
500
2300
3700
2900
200
130
130
370
9000
170
C
230
9000
3700
9000
Round 232 to the nearest tenC
Round 3,701 to the nearest hundredN
Round 51 to the nearest tenL
Round 720 to the nearest hundredR
Round 174 to the nearest tenS
Round 466 to the nearest hundredO
Round 2,281 to the nearest thousandB
Round 3,171 to the nearest thousandF
Round 24 to the nearest tenK
Round 223 to the nearest hundredA
Round 8,661 to the nearest thousandE
Round 2,930 to the nearest hundredD
Round 373 to the nearest tenH
Round 2,324 to the nearest hundredU
Round 134 to the nearest tenT
Round 4,309 to the nearest hundredW
Round 5,118 to the nearest thousandI
Round 34 to the nearest tenY
0/18 letters found
Clue 5
Division facts (1-12) — the last clue
Splitting the total number of recovered data fragments equally across our storage drives yielded the final hint.
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
60 ÷ 5 = ?
32 ÷ 4 = ?
14 ÷ 7 = ?
30 ÷ 5 = ?
77 ÷ 11 = ?
110 ÷ 10 = ?
40 ÷ 10 = ?
40 ÷ 4 = ?
12 ÷ 12 = ?
6 ÷ 2 = ?
54 ÷ 6 = ?
Step 2 — cross out the sentence with each answer
1.The villain zoomed ahead with a vector dash, then locked the vault with a logarithm trap.
2.The villain blasted light with a calculus beam, then struck hard with a binary spike.
3.The villain blocked attacks with a geometry shield, then jammed systems with a graph pulse.
4.The villain blasted light with a calculus beam, then locked the vault with a logarithm trap.
5.The villain created patterns with a fractal blast, then jammed systems with a graph pulse.
6.The villain blocked attacks with a geometry shield, then struck hard with a binary spike.
7.The villain blocked attacks with a geometry shield, then trapped the guard in a pi sphere.
8.The villain created patterns with a fractal blast, then struck hard with a binary spike.
9.The villain created patterns with a fractal blast, then trapped the guard in a pi sphere.
10.The villain blocked attacks with a geometry shield, then raised a prime barrier.
11.The villain blasted light with a calculus beam, then raised a prime barrier.
12.The villain warped space with a matrix shift, then jammed systems with a graph pulse.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Case of the Miscalculated Mastermind
Culprit: Katherine Johnson (Fractal Blast · Graph Pulse · Tapping a Pencil · Curly Ink Black · Division by Zero)
- Clue 1 (Fractions of a number): "THE VILLAIN DOES NOT USE LOGARITHM TRAP"1/2 of 46 = 23 (T) · 3/6 of 66 = 33 (L) · 2/6 of 108 = 36 (P) · 1/5 of 145 = 29 (H) · 2/4 of 36 = 18 (V) · 3/5 of 45 = 27 (D) · 1/3 of 117 = 39 (I) · 3/6 of 6 = 3 (O) · 1/6 of 66 = 11 (E) · 2/4 of 62 = 31 (M) · 1/3 of 120 = 40 (A) · 1/10 of 40 = 4 (S) · 2/8 of 56 = 14 (G) · 1/5 of 45 = 9 (R) · 2/10 of 175 = 35 (U) · 2/4 of 42 = 21 (N)
- Clue 2 (Order of operations): "THE SUSPECT WAS SEEN TAPPING A PENCIL"12 × 7 - 11 = 73 (T) · 10 × 9 - 24 = 66 (U) · 6 × 3 - 11 = 7 (S) · 53 + 4 × 4 = 69 (L) · 12 × 4 - 16 = 32 (E) · 9 × 9 - 18 = 63 (W) · 7 × 5 - 26 = 9 (C) · 11 × 7 - 29 = 48 (H) · 5 × 11 - 26 = 29 (N) · 9 × 5 - 23 = 22 (A) · 12 × 6 - 21 = 51 (P) · 6 × 6 - 23 = 13 (I) · 10 + 3 × 8 = 34 (G)
- Clue 3 (Multiplication facts (1-12)): "THE VILLAIN WAS STOPPED BY DIVISION BY ZERO"11 × 2 = 22 (T) · 12 × 7 = 84 (P) · 8 × 5 = 40 (H) · 12 × 1 = 12 (Y) · 6 × 4 = 24 (A) · 8 × 8 = 64 (E) · 6 × 9 = 54 (B) · 7 × 2 = 14 (W) · 7 × 10 = 70 (S) · 11 × 12 = 132 (L) · 7 × 1 = 7 (D) · 8 × 6 = 48 (R) · 9 × 12 = 108 (I) · 10 × 8 = 80 (N) · 11 × 3 = 33 (Z) · 7 × 8 = 56 (V) · 2 × 1 = 2 (O)
- Clue 4 (Rounding): "CURLY INK BLACK HAIR WAS FOUND AT THE SCENE"Round 232 to the nearest ten = 230 (C) · Round 3,701 to the nearest hundred = 3700 (N) · Round 51 to the nearest ten = 50 (L) · Round 720 to the nearest hundred = 700 (R) · Round 174 to the nearest ten = 170 (S) · Round 466 to the nearest hundred = 500 (O) · Round 2,281 to the nearest thousand = 2000 (B) · Round 3,171 to the nearest thousand = 3000 (F) · Round 24 to the nearest ten = 20 (K) · Round 223 to the nearest hundred = 200 (A) · Round 8,661 to the nearest thousand = 9000 (E) · Round 2,930 to the nearest hundred = 2900 (D) · Round 373 to the nearest ten = 370 (H) · Round 2,324 to the nearest hundred = 2300 (U) · Round 134 to the nearest ten = 130 (T) · Round 4,309 to the nearest hundred = 4300 (W) · Round 5,118 to the nearest thousand = 5000 (I) · Round 34 to the nearest ten = 30 (Y)
- Clue 5 (Division facts (1-12)): surviving statement (box 5) → Katherine Johnson60 ÷ 5 = 12 · 32 ÷ 4 = 8 · 14 ÷ 7 = 2 · 30 ÷ 5 = 6 · 77 ÷ 11 = 7 · 110 ÷ 10 = 11 · 40 ÷ 10 = 4 · 40 ÷ 4 = 10 · 12 ÷ 12 = 1 · 6 ÷ 2 = 3 · 54 ÷ 6 = 9
About this mystery
- Grade level
- Grade 5 math
- Math topics
- Fractions of a number, Order of operations, Multiplication, Rounding, Division
- Reading level
- grades 5-6
- Theme
- The Case of the Miscalculated Mastermind — set in The National Academy of Mathematics
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects