🦕 DinosaursGrade 1Reading: grades 1-2AdditionSubtractionSkip countingPlace valueMissing addends
The Great Fossil Mystery
A rare glowing dino egg went missing from the camp tent! The trackers left clue notes around the dig site to help you figure out who took it.
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 | Dino Move | Special Gear | Dominant Hand | Head Feathers | Scare Tool |
|---|---|---|---|---|---|
| Pete Pick | Rex Roar | Mud Glide | Left Handed | Green Crest | Loud Whistle |
| Palaeo Pam | Trike Charge | Mud Glide | Left Handed | Blue Spikes | Squeaky Toy |
| Maya Fossil | Stego Tail | Lava Shield | Left Handed | Blue Spikes | Squeaky Toy |
| Professor Dino | Rex Roar | Rock Armor | Left Handed | Blue Spikes | Loud Whistle |
| Quinn Quartz | Stego Tail | Rock Armor | Left Handed | Green Crest | Squeaky Toy |
| Rocky Rex | Rex Roar | Camouflage | Left Handed | Blue Spikes | Bright Flashlight |
| Tracker Tim | Stego Tail | Mud Glide | Left Handed | Green Crest | Squeaky Toy |
| Chisel Chet | Stego Tail | Camouflage | Left Handed | Blue Spikes | Bright Flashlight |
| Jack Jaw | Stego Tail | Lava Shield | Left Handed | Blue Spikes | Bright Flashlight |
| Opal Oval | Ptero Flight | Camouflage | Left Handed | Green Crest | Bright Flashlight |
| Gigi Ground | Rex Roar | Rock Armor | Left Handed | Red Feathers | Bright Flashlight |
| Nate Nest | Ptero Flight | Mud Glide | Right Handed | Red Feathers | Squeaky Toy |
| Sammy Scale | Ptero Flight | Camouflage | Left Handed | Blue Spikes | Bright Flashlight |
| Ivy Ivory | Raptor Speed | Rock Armor | Left Handed | Blue Spikes | Bright Flashlight |
| Kira King | Stego Tail | Night Vision | Left Handed | Blue Spikes | Loud Whistle |
| Fossil Fred | Raptor Speed | Camouflage | Left Handed | Blue Spikes | Squeaky Toy |
| Amber Ann | Raptor Speed | Rock Armor | Right Handed | Blue Spikes | Bright Flashlight |
| Dr Bones | Trike Charge | Camouflage | Left Handed | Green Crest | Bright Flashlight |
| Ranger Rita | Ptero Flight | Camouflage | Left Handed | Blue Spikes | Squeaky Toy |
| Digging Dan | Raptor Speed | Mud Glide | Right Handed | Blue Spikes | Loud Whistle |
| Mona Mud | Raptor Speed | Rock Armor | Left Handed | Blue Spikes | Squeaky Toy |
Clue 1
Addition
You add up all the fossil brushes found near the tent to unlock Clue 1.
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
5
13
16
6
11
16
15
18
8
3
16
6
11
3
T
5
13
15
4
16
20
15
4
15
6
13
19
16
20
8
3 + 2 =T
5 + 13 =K
5 + 8 =H
2 + 6 =D
2 + 4 =S
2 + 1 =O
1 + 3 =V
7 + 9 =E
8 + 7 =A
11 + 8 =I
4 + 7 =N
13 + 7 =L
0/12 letters found
Clue 2
Subtraction
You take away the broken eggshells from the batch to find Clue 2.
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
8
10
12
19
2
19
4
12
3
T
8
15
19
1
12
16
T
8
10
6
13
7
12
7
16 - 8 =T
13 - 7 =A
9 - 6 =C
3 - 2 =L
20 - 1 =S
17 - 7 =H
8 - 4 =P
14 - 1 =N
8 - 1 =D
14 - 2 =E
18 - 2 =F
20 - 5 =I
10 - 8 =U
0/13 letters found
Clue 3
Skip counting
You skip count the big dino footprints in twos across the mud to reveal Clue 3.
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
35
60
40
39
22
30
45
9
24
A
35
12
30
24
39
22
30
45
12
36
A
35
40
25
27
45
30
25
45
30
39
25
9
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45A
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45I
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16S
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, ___, 45, 50R
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55T
Skip-count by 3s. Fill the blank: 3, 6, ___, 12, 15F
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, ___, 70, 80B
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, ___, 39, 42C
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, ___, 24, 26G
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, ___, 26, 28L
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, ___, 30, 33D
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35E
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, ___, 33, 36H
0/13 letters found
Clue 4
Place value
You break down the count of amber gems into tens and ones to decode Clue 4.
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
36
24
78
72
40
74
79
33
98
40
24
28
75
30
93
24
28
69
49
49
18
24
28
65
24
74
24
What number has 3 tens and 6 ones?W
What number has 7 tens and 9 ones?D
What number has 9 tens and 8 ones?L
What number has 7 tens and 5 ones?P
What number has 2 tens and 8 ones?S
What number has 7 tens and 8 ones?F
What number has 2 tens and 4 ones?E
What number has 3 tens and 3 ones?B
What number has 4 tens and 0 ones?U
What number has 6 tens and 9 ones?A
What number has 1 ten and 8 ones?H
What number has 9 tens and 3 ones?K
What number has 7 tens and 4 ones?N
What number has 3 tens and 0 ones?I
What number has 6 tens and 5 ones?C
What number has 7 tens and 2 ones?O
What number has 4 tens and 9 ones?T
0/17 letters found
Clue 5
Missing addends — the last clue
You find the missing number of bone pieces needed for the skeleton to reach Clue 5.
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
2 + ___ = 13
6 + ___ = 16
9 + ___ = 10
6 + ___ = 10
7 + ___ = 9
3 + ___ = 6
10 + ___ = 19
6 + ___ = 11
6 + ___ = 18
8 + ___ = 16
3 + ___ = 10
Step 2 — cross out the sentence with each answer
1.The villain soared on pterodactyl wings, then blended in with camouflage.
2.The villain ran with raptor speed, then slid away with a mud glide.
3.The villain charged like a trike, then blended in with camouflage.
4.The villain charged like a trike, then slid away with a mud glide.
5.The villain swung a stegosaurus tail, then slid away with a mud glide.
6.The villain roared like a rex, then blended in with camouflage.
7.The villain soared on pterodactyl wings, then slid away with a mud glide.
8.The villain swung a stegosaurus tail, then put on heavy rock armor.
9.The villain ran with raptor speed, then used night vision.
10.The villain ran with raptor speed, then put on heavy rock armor.
11.The villain swung a stegosaurus tail, then blended in with camouflage.
12.The villain roared like a rex, then slid away with a mud glide.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Great Fossil Mystery
Culprit: Rocky Rex (Rex Roar · Camouflage · Left Handed · Blue Spikes · Bright Flashlight)
- Clue 1 (Addition): "THE SNEAK DOES NOT HAVE LAVA SHIELD"3 + 2 = 5 (T) · 5 + 13 = 18 (K) · 5 + 8 = 13 (H) · 2 + 6 = 8 (D) · 2 + 4 = 6 (S) · 2 + 1 = 3 (O) · 1 + 3 = 4 (V) · 7 + 9 = 16 (E) · 8 + 7 = 15 (A) · 11 + 8 = 19 (I) · 4 + 7 = 11 (N) · 13 + 7 = 20 (L)
- Clue 2 (Subtraction): "THE SUSPECT IS LEFT HANDED"16 - 8 = 8 (T) · 13 - 7 = 6 (A) · 9 - 6 = 3 (C) · 3 - 2 = 1 (L) · 20 - 1 = 19 (S) · 17 - 7 = 10 (H) · 8 - 4 = 4 (P) · 14 - 1 = 13 (N) · 8 - 1 = 7 (D) · 14 - 2 = 12 (E) · 18 - 2 = 16 (F) · 20 - 5 = 15 (I) · 10 - 8 = 2 (U)
- Clue 3 (Skip counting): "A BRIGHT FLASHLIGHT SCARED THE THIEF"Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45 = 35 (A) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45 = 39 (I) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16 = 12 (S) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, ___, 45, 50 = 40 (R) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55 = 45 (T) · Skip-count by 3s. Fill the blank: 3, 6, ___, 12, 15 = 9 (F) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, ___, 70, 80 = 60 (B) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, ___, 39, 42 = 36 (C) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, ___, 24, 26 = 22 (G) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, ___, 26, 28 = 24 (L) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, ___, 30, 33 = 27 (D) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35 = 25 (E) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, ___, 33, 36 = 30 (H)
- Clue 4 (Place value): "WE FOUND BLUE SPIKES AT THE SCENE"What number has 3 tens and 6 ones? = 36 (W) · What number has 7 tens and 9 ones? = 79 (D) · What number has 9 tens and 8 ones? = 98 (L) · What number has 7 tens and 5 ones? = 75 (P) · What number has 2 tens and 8 ones? = 28 (S) · What number has 7 tens and 8 ones? = 78 (F) · What number has 2 tens and 4 ones? = 24 (E) · What number has 3 tens and 3 ones? = 33 (B) · What number has 4 tens and 0 ones? = 40 (U) · What number has 6 tens and 9 ones? = 69 (A) · What number has 1 ten and 8 ones? = 18 (H) · What number has 9 tens and 3 ones? = 93 (K) · What number has 7 tens and 4 ones? = 74 (N) · What number has 3 tens and 0 ones? = 30 (I) · What number has 6 tens and 5 ones? = 65 (C) · What number has 7 tens and 2 ones? = 72 (O) · What number has 4 tens and 9 ones? = 49 (T)
- Clue 5 (Missing addends): surviving statement (box 6) → Rocky Rex2 + ___ = 13 = 11 · 6 + ___ = 16 = 10 · 9 + ___ = 10 = 1 · 6 + ___ = 10 = 4 · 7 + ___ = 9 = 2 · 3 + ___ = 6 = 3 · 10 + ___ = 19 = 9 · 6 + ___ = 11 = 5 · 6 + ___ = 18 = 12 · 8 + ___ = 16 = 8 · 3 + ___ = 10 = 7
About this mystery
- Grade level
- Grade 1 math
- Math topics
- Addition, Subtraction, Skip counting, Place value, Missing addends
- Reading level
- grades 1-2
- Theme
- The Great Fossil Mystery — set in Dino Valley Camp
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects