🦕 DinosaursGrade 7Reading: grades 7-9IntegersWord problemsMulti-step word problemsPercentagesMissing addends
The Mystery of the Missing T-Rex Skull
A priceless, fully intact Tyrannosaurus Rex skull has vanished overnight from the central excavation pit. Suspicion falls upon twenty-four field researchers and expedition crew members currently on location.
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 | Habitual Tell | Headwear Color | Vulnerability |
|---|---|---|---|---|---|
| Gideon Mantell | Sonic Bone Scanner | Amber Sample Kit | Taps Digging Trowel | Slate Gray Helmet | Distracted By Fossilized Shells |
| Anusuya Chinsamy | Sonic Bone Scanner | Specimen Lockbox | Whistles Trail Songs | Rust Brown Bandana | Sneezing From Chalk Dust |
| Jack Horner | Geological Radar | Surveying Transit | Whistles Trail Songs | Slate Gray Helmet | Distracted By Fossilized Shells |
| Phil Currie | Plaster Casting Rig | Isotope Analyzer | Taps Digging Trowel | Dusty Gold Cap | Distracted By Fossilized Shells |
| Dr Alan Grant | Pneumatic Chisel | Isotope Analyzer | Taps Digging Trowel | Slate Gray Helmet | Sneezing From Chalk Dust |
| Patricia Vickers | Sonic Bone Scanner | Isotope Analyzer | Taps Digging Trowel | Rust Brown Bandana | Startled By Rockfalls |
| Paul Barrett | Pneumatic Chisel | Specimen Lockbox | Whistles Trail Songs | Rust Brown Bandana | Startled By Rockfalls |
| Jingmai OConnor | Geological Radar | Surveying Transit | Taps Digging Trowel | Rust Brown Bandana | Startled By Rockfalls |
| Othniel Marsh | Pneumatic Chisel | Surveying Transit | Taps Digging Trowel | Dusty Gold Cap | Sneezing From Chalk Dust |
| Dr Ellie Sattler | Pneumatic Chisel | Specimen Lockbox | Taps Digging Trowel | Rust Brown Bandana | Distracted By Fossilized Shells |
| Paul Sereno | Sonic Bone Scanner | Specimen Lockbox | Taps Digging Trowel | Rust Brown Bandana | Startled By Rockfalls |
| Dr Ian Malcolm | Geological Radar | Surveying Transit | Whistles Trail Songs | Rust Brown Bandana | Sneezing From Chalk Dust |
| Steve Brusatte | Sonic Bone Scanner | Specimen Lockbox | Whistles Trail Songs | Slate Gray Helmet | Distracted By Fossilized Shells |
| Luis Chiappe | Pneumatic Chisel | Amber Sample Kit | Taps Digging Trowel | Rust Brown Bandana | Startled By Rockfalls |
| Edward Cope | Pneumatic Chisel | Magnifying Monocle | Taps Digging Trowel | Rust Brown Bandana | Startled By Rockfalls |
| Xu Xing | Pneumatic Chisel | Amber Sample Kit | Whistles Trail Songs | Slate Gray Helmet | Startled By Rockfalls |
| Barnum Brown | Plaster Casting Rig | Isotope Analyzer | Whistles Trail Songs | Dusty Gold Cap | Startled By Rockfalls |
| Karen Chin | Plaster Casting Rig | Surveying Transit | Whistles Trail Songs | Dusty Gold Cap | Distracted By Fossilized Shells |
| Lindsay Zanno | Pneumatic Chisel | Surveying Transit | Whistles Trail Songs | Slate Gray Helmet | Startled By Rockfalls |
| Rodolfo Coria | Pneumatic Chisel | Amber Sample Kit | Whistles Trail Songs | Rust Brown Bandana | Startled By Rockfalls |
| Mary Anning | Plaster Casting Rig | Surveying Transit | Taps Digging Trowel | Slate Gray Helmet | Startled By Rockfalls |
Clue 1
Integers
To calculate the total volume of earth moved overnight from the quarry, complete the multi-step excavation totals.
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
10
26
30
1
17
9
9
20
17
5
2
25
30
29
5
25
T
10
12
29
30
20
14
20
24
5
17
6
27
17
5
24
14
25
5
25
11
9
30
(-13) + 23 =T
13 - (-4) =I
6 - (-3) =L
(-7) + 18 =C
(-3) + 33 =E
22 - (-3) =O
6 - (-14) =A
(-6) + 8 =D
(-8) + 13 =N
(-11) + 23 =U
(-11) + 12 =V
(-8) + 37 =S
(-1) + 15 =M
9 - (-15) =G
21 - (-5) =H
(-7) + 13 =F
15 - (-12) =Y
0/17 letters found
Clue 2
Word problems
Analyze these dig site supply logs to determine which paleontology stations were active during the heist.
Solve each problem to learn its letter, then write the letters in the boxes to fill in the missing word.
Awitnesssawthevillainwas .
T
48
91
45
100
85
93
15
15
93
N
15
T
48
R
O
W
E
L
Dinosaur researcher found 38 measuring tapes yesterday and 10 more today. How many measuring tapes in all?T
There were 118 sediment samples. 33 were used up. How many sediment samples are left?D
Dinosaur researcher found 6 measuring tapes yesterday and 87 more today. How many measuring tapes in all?I
Dinosaur researcher found 48 ammonite shells yesterday and 52 more today. How many ammonite shells in all?S
Dinosaur researcher found 23 raptor claws yesterday and 68 more today. How many raptor claws in all?A
Dinosaur researcher found 3 ammonite shells yesterday and 12 more today. How many ammonite shells in all?G
Dinosaur researcher found 8 ammonite shells yesterday and 37 more today. How many ammonite shells in all?P
0/7 letters found
Clue 3
Multi-step word problems
Check the depth readings and elevation changes relative to sea level across the dig grid.
Solve each problem to learn its letter, then write the letters in the boxes to fill in the missing word.
Someonescaredthevillainoffwith .
S
78
51
37
14
51
54
68
74
B
Y
14
O
C
K
F
37
54
54
S
78
There were 419 sediment samples in all. 1 expedition crew used 29 sediment samples each. The other 5 expedition crew shared the rest equally. How many sediment samples did each of the other expedition crew get?S
Dinosaur researcher collected 22 raptor claws in the morning and 6 raptor claws in the afternoon, then split them equally among 2 expedition crew. How many raptor claws did each get?R
There were 177 sediment samples in all. 3 expedition crew used 22 sediment samples each. The other 3 expedition crew shared the rest equally. How many sediment samples did each of the other expedition crew get?A
Dinosaur researcher filled 9 boxes with 5 fossilized teeth each, then found 9 more fossilized teeth. How many fossilized teeth are there in all?L
Dinosaur researcher collected 282 measuring tapes in the morning and 88 measuring tapes in the afternoon, then split them equally among 5 expedition crew. How many measuring tapes did each get?D
Dinosaur researcher earned 8 fossilized teeth in each of 5 rounds, plus 34 bonus fossilized teeth. Then 6 fossilized teeth were lost. How many fossilized teeth are left?E
Dinosaur researcher collected 68 measuring tapes in the morning and 187 measuring tapes in the afternoon, then split them equally among 5 expedition crew. How many measuring tapes did each get?T
0/7 letters found
Clue 4
Percentages
Determine the mineral concentration percentages found in the surrounding rock strata samples.
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
18
1
31
6
A
18
59
16
34
10
6
20
1
31
7
6
34
45
59
10
A
18
7
6
51
27
45
A
18
1
10
34
20
59
16
5% of 360 =A
75% of 60 =W
5% of 680 =O
5% of 140 =B
5% of 20 =S
60% of 45 =C
50% of 32 =D
5% of 620 =T
60% of 10 =R
40% of 25 =F
25% of 204 =I
20% of 295 =N
25% of 80 =U
0/13 letters found
Clue 5
Missing addends — the last clue
Fill in the missing bone fragment tallies to finish auditing the quarry inventory log.
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
30 + ___ = 41
22 + ___ = 34
35 + ___ = 38
27 + ___ = 34
30 + ___ = 34
5 + ___ = 10
5 + ___ = 6
19 + ___ = 21
17 + ___ = 27
11 + ___ = 17
7 + ___ = 15
Step 2 — cross out the sentence with each answer
1.The villain calibrated the sonic bone scanner, then packed an amber sample kit.
2.The villain scanned with geological radar, then ran the isotope analyzer.
3.The villain scanned with geological radar, then leveled a surveying transit.
4.The villain applied a plaster casing, then secured the specimen lockbox.
5.The villain scanned with geological radar, then packed an amber sample kit.
6.The villain calibrated the sonic bone scanner, then adjusted a magnifying monocle.
7.The villain flew a laser mapping drone, then packed an amber sample kit.
8.The villain applied a plaster casing, then ran the isotope analyzer.
9.The villain chiseled through heavy shale, then packed an amber sample kit.
10.The villain flew a laser mapping drone, then leveled a surveying transit.
11.The villain calibrated the sonic bone scanner, then ran the isotope analyzer.
12.The villain calibrated the sonic bone scanner, then secured the specimen lockbox.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Mystery of the Missing T-Rex Skull
Culprit: Luis Chiappe (Pneumatic Chisel · Amber Sample Kit · Taps Digging Trowel · Rust Brown Bandana · Startled By Rockfalls)
- Clue 1 (Integers): "THE VILLAIN DOES NOT USE A MAGNIFYING MONOCLE"(-13) + 23 = 10 (T) · 13 - (-4) = 17 (I) · 6 - (-3) = 9 (L) · (-7) + 18 = 11 (C) · (-3) + 33 = 30 (E) · 22 - (-3) = 25 (O) · 6 - (-14) = 20 (A) · (-6) + 8 = 2 (D) · (-8) + 13 = 5 (N) · (-11) + 23 = 12 (U) · (-11) + 12 = 1 (V) · (-8) + 37 = 29 (S) · (-1) + 15 = 14 (M) · 9 - (-15) = 24 (G) · 21 - (-5) = 26 (H) · (-7) + 13 = 6 (F) · 15 - (-12) = 27 (Y)
- Clue 2 (Word problems): "TAPS DIGGING TROWEL"Dinosaur researcher found 38 measuring tapes yesterday and 10 more today. How many measuring tapes in all? = 48 (T) · There were 118 sediment samples. 33 were used up. How many sediment samples are left? = 85 (D) · Dinosaur researcher found 6 measuring tapes yesterday and 87 more today. How many measuring tapes in all? = 93 (I) · Dinosaur researcher found 48 ammonite shells yesterday and 52 more today. How many ammonite shells in all? = 100 (S) · Dinosaur researcher found 23 raptor claws yesterday and 68 more today. How many raptor claws in all? = 91 (A) · Dinosaur researcher found 3 ammonite shells yesterday and 12 more today. How many ammonite shells in all? = 15 (G) · Dinosaur researcher found 8 ammonite shells yesterday and 37 more today. How many ammonite shells in all? = 45 (P)
- Clue 3 (Multi-step word problems): "STARTLED BY ROCKFALLS"There were 419 sediment samples in all. 1 expedition crew used 29 sediment samples each. The other 5 expedition crew shared the rest equally. How many sediment samples did each of the other expedition crew get? = 78 (S) · Dinosaur researcher collected 22 raptor claws in the morning and 6 raptor claws in the afternoon, then split them equally among 2 expedition crew. How many raptor claws did each get? = 14 (R) · There were 177 sediment samples in all. 3 expedition crew used 22 sediment samples each. The other 3 expedition crew shared the rest equally. How many sediment samples did each of the other expedition crew get? = 37 (A) · Dinosaur researcher filled 9 boxes with 5 fossilized teeth each, then found 9 more fossilized teeth. How many fossilized teeth are there in all? = 54 (L) · Dinosaur researcher collected 282 measuring tapes in the morning and 88 measuring tapes in the afternoon, then split them equally among 5 expedition crew. How many measuring tapes did each get? = 74 (D) · Dinosaur researcher earned 8 fossilized teeth in each of 5 rounds, plus 34 bonus fossilized teeth. Then 6 fossilized teeth were lost. How many fossilized teeth are left? = 68 (E) · Dinosaur researcher collected 68 measuring tapes in the morning and 187 measuring tapes in the afternoon, then split them equally among 5 expedition crew. How many measuring tapes did each get? = 51 (T)
- Clue 4 (Percentages): "A STRAND OF RUST BROWN FABRIC WAS FOUND"5% of 360 = 18 (A) · 75% of 60 = 45 (W) · 5% of 680 = 34 (O) · 5% of 140 = 7 (B) · 5% of 20 = 1 (S) · 60% of 45 = 27 (C) · 50% of 32 = 16 (D) · 5% of 620 = 31 (T) · 60% of 10 = 6 (R) · 40% of 25 = 10 (F) · 25% of 204 = 51 (I) · 20% of 295 = 59 (N) · 25% of 80 = 20 (U)
- Clue 5 (Missing addends): surviving statement (box 9) → Luis Chiappe30 + ___ = 41 = 11 · 22 + ___ = 34 = 12 · 35 + ___ = 38 = 3 · 27 + ___ = 34 = 7 · 30 + ___ = 34 = 4 · 5 + ___ = 10 = 5 · 5 + ___ = 6 = 1 · 19 + ___ = 21 = 2 · 17 + ___ = 27 = 10 · 11 + ___ = 17 = 6 · 7 + ___ = 15 = 8
About this mystery
- Grade level
- Grade 7 math
- Math topics
- Integers, Word problems, Multi-step word problems, Percentages, Missing addends
- Reading level
- grades 7-9
- Theme
- The Mystery of the Missing T-Rex Skull — set in The Cretan Basin Dig Site
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects