Grade 1Reading: grades 1-2AdditionSubtractionSkip countingPlace valueMissing addends
The Great Treehouse Camp Mystery
Oh no! The Golden Marshmallow Trophy is gone! Someone took it from the main campfire circle right before the big camp party. Leader Sam needs your help to follow the clues, track down the sneaky culprit, and save the summer camp celebration!
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 | Camp Gear | Camp Badge | Hand Trait | Cap Color | Fear |
|---|---|---|---|---|---|
| Wyatt | canteen | cooking badge | right-handed | green cap | dark caves |
| Max | flashlight | canoe badge | right-handed | green cap | dark caves |
| Milo | canteen | knot badge | right-handed | blue cap | frogs |
| Otis | canteen | hiking badge | right-handed | green cap | frogs |
| Penny | binoculars | knot badge | right-handed | green cap | frogs |
| Toby | compass | canoe badge | left-handed | green cap | frogs |
| Piper | binoculars | cooking badge | right-handed | red cap | spiderwebs |
| Billy | binoculars | cooking badge | right-handed | red cap | frogs |
| Hazel | flashlight | cooking badge | right-handed | blue cap | spiderwebs |
| Zoe | flashlight | knot badge | right-handed | red cap | frogs |
| Daisy | map | knot badge | right-handed | green cap | dark caves |
| Scout | compass | hiking badge | left-handed | red cap | dark caves |
| Finn | canteen | tent badge | right-handed | red cap | frogs |
| Ruby | flashlight | canoe badge | left-handed | red cap | frogs |
| Ryder | flashlight | hiking badge | right-handed | red cap | spiderwebs |
| Jack | compass | canoe badge | right-handed | red cap | frogs |
| Clover | flashlight | tent badge | left-handed | green cap | spiderwebs |
| Emma | compass | cooking badge | right-handed | red cap | dark caves |
| Jax | canteen | cooking badge | left-handed | red cap | frogs |
| Lily | binoculars | cooking badge | left-handed | red cap | dark caves |
| Maya | flashlight | hiking badge | right-handed | red cap | frogs |
Clue 1
Addition
We find a notepad on the ground. We add three blue pens and four red pens to count the clues.
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
14
18
20
3
9
8
17
16
T
14
17
12
20
10
8
12
T
14
18
9
19
20
9
2
9
8
12
20
3
9
17
13
20
6 + 8 =T
1 + 1 =C
7 + 5 =O
6 + 2 =N
11 + 5 =I
8 + 11 =V
4 + 6 =S
7 + 2 =A
1 + 2 =B
10 + 10 =E
11 + 6 =D
9 + 4 =G
8 + 10 =H
0/13 letters found
Clue 2
Subtraction
The camp kitchen is messy. We had ten apples but five are missing now. This points us to the next hint.
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
19
7
13
18
1
4
12
T
5
17
7
18
14
19
7
4
6
8
T
5
11
12
T
5
19
T
5
19
7
12
17
17
12
3
19
T
5
19
18
1
4
9 - 4 =T
10 - 3 =E
13 - 1 =I
20 - 1 =H
15 - 1 =C
14 - 6 =U
19 - 1 =A
20 - 3 =R
20 - 9 =W
19 - 6 =B
12 - 9 =G
8 - 7 =N
12 - 6 =O
10 - 6 =D
0/14 letters found
Clue 3
Skip counting
We follow muddy boot prints on the trail. We count them by twos to see where they go.
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
18
15
33
35
6
30
39
65
T
18
120
6
30
6
60
6
8
60
15
33
30
6
12
120
90
10
9
50
21
20
33
39
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, ___, 20, 22T
Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10A
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, ___, 12, 14G
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, ___, 65, 70W
Skip-count by 10s. Fill the blank: 10, 20, ___, 40, 50N
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45B
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27M
Skip-count by 2s. Fill the blank: 2, 4, 6, ___, 10, 12Y
Skip-count by 3s. Fill the blank: 3, 6, ___, 12, 15J
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, ___, 18, 21H
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75I
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, ___, 22, 24P
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ___, 36, 39E
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70U
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, ___, 130, 140R
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110O
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16F
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45D
0/18 letters found
Clue 4
Place value
We find a pile of shiny pinecones. They are grouped into tens and ones. The total number unlocks a clue.
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
24
99
78
88
91
42
48
78
58
74
48
42
78
58
A
24
74
16
A
24
70
36
58
26
48
81
25
48
42
58
78
81
29
58
What number has 2 tens and 4 ones?A
What number has 2 tens and 5 ones?N
What number has 8 tens and 8 ones?I
What number has 5 tens and 8 ones?E
What number has 7 tens and 0 ones?S
What number has 4 tens and 2 ones?H
What number has 7 tens and 8 ones?R
What number has 1 ten and 6 ones?W
What number has 9 tens and 9 ones?B
What number has 9 tens and 1 one?G
What number has 2 tens and 9 ones?P
What number has 3 tens and 6 ones?L
What number has 4 tens and 8 ones?T
What number has 2 tens and 6 ones?F
What number has 7 tens and 4 ones?D
What number has 8 tens and 1 one?O
0/16 letters found
Clue 5
Missing addends — the last clue
The snack box needs eight juice boxes. There are only six inside. We must find how many are gone.
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
7 + ___ = 8
10 + ___ = 17
1 + ___ = 13
4 + ___ = 13
4 + ___ = 9
6 + ___ = 14
8 + ___ = 18
6 + ___ = 10
6 + ___ = 17
10 + ___ = 16
6 + ___ = 8
Step 2 — cross out the sentence with each answer
1.The villain sneaks past the sleeping tents, then disappears into the tall ferns.
2.The villain sneaks past the sleeping tents, then hides in the hollow oak.
3.The villain climbs up the wooden ladder, then hides in the hollow oak.
4.The villain sneaks past the sleeping tents, then jumps over the campfire logs.
5.The villain swings on a rope bridge, then hides in the hollow oak.
6.The villain paddles across the quiet lake, then hides in the hollow oak.
7.The villain paddles across the quiet lake, then creeps into the mess hall.
8.The villain climbs up the wooden ladder, then disappears into the tall ferns.
9.The villain zips down the long zip line, then creeps into the mess hall.
10.The villain zips down the long zip line, then runs down the muddy trail.
11.The villain zips down the long zip line, then hides in the hollow oak.
12.The villain climbs up the wooden ladder, then runs down the muddy trail.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Great Treehouse Camp Mystery
Culprit: Maya (flashlight · hiking badge · right-handed · red cap · frogs)
- Clue 1 (Addition): "THE BANDIT DOES NOT HAVE A CANOE BADGE"6 + 8 = 14 (T) · 1 + 1 = 2 (C) · 7 + 5 = 12 (O) · 6 + 2 = 8 (N) · 11 + 5 = 16 (I) · 8 + 11 = 19 (V) · 4 + 6 = 10 (S) · 7 + 2 = 9 (A) · 1 + 2 = 3 (B) · 10 + 10 = 20 (E) · 11 + 6 = 17 (D) · 9 + 4 = 13 (G) · 8 + 10 = 18 (H)
- Clue 2 (Subtraction): "THE BANDIT REACHED OUT WITH THEIR RIGHT HAND"9 - 4 = 5 (T) · 10 - 3 = 7 (E) · 13 - 1 = 12 (I) · 20 - 1 = 19 (H) · 15 - 1 = 14 (C) · 14 - 6 = 8 (U) · 19 - 1 = 18 (A) · 20 - 3 = 17 (R) · 20 - 9 = 11 (W) · 19 - 6 = 13 (B) · 12 - 9 = 3 (G) · 8 - 7 = 1 (N) · 12 - 6 = 6 (O) · 10 - 6 = 4 (D)
- Clue 3 (Skip counting): "THE BANDIT RAN AWAY WHEN A FROG JUMPED"Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, ___, 20, 22 = 18 (T) · Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10 = 6 (A) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, ___, 12, 14 = 10 (G) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, ___, 65, 70 = 60 (W) · Skip-count by 10s. Fill the blank: 10, 20, ___, 40, 50 = 30 (N) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45 = 35 (B) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27 = 21 (M) · Skip-count by 2s. Fill the blank: 2, 4, 6, ___, 10, 12 = 8 (Y) · Skip-count by 3s. Fill the blank: 3, 6, ___, 12, 15 = 9 (J) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, ___, 18, 21 = 15 (H) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75 = 65 (I) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, ___, 22, 24 = 20 (P) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ___, 36, 39 = 33 (E) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70 = 50 (U) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, ___, 130, 140 = 120 (R) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110 = 90 (O) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16 = 12 (F) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45 = 39 (D)
- Clue 4 (Place value): "A BRIGHT RED THREAD WAS LEFT ON THE ROPE"What number has 2 tens and 4 ones? = 24 (A) · What number has 2 tens and 5 ones? = 25 (N) · What number has 8 tens and 8 ones? = 88 (I) · What number has 5 tens and 8 ones? = 58 (E) · What number has 7 tens and 0 ones? = 70 (S) · What number has 4 tens and 2 ones? = 42 (H) · What number has 7 tens and 8 ones? = 78 (R) · What number has 1 ten and 6 ones? = 16 (W) · What number has 9 tens and 9 ones? = 99 (B) · What number has 9 tens and 1 one? = 91 (G) · What number has 2 tens and 9 ones? = 29 (P) · What number has 3 tens and 6 ones? = 36 (L) · What number has 4 tens and 8 ones? = 48 (T) · What number has 2 tens and 6 ones? = 26 (F) · What number has 7 tens and 4 ones? = 74 (D) · What number has 8 tens and 1 one? = 81 (O)
- Clue 5 (Missing addends): surviving statement (box 3) → Maya7 + ___ = 8 = 1 · 10 + ___ = 17 = 7 · 1 + ___ = 13 = 12 · 4 + ___ = 13 = 9 · 4 + ___ = 9 = 5 · 6 + ___ = 14 = 8 · 8 + ___ = 18 = 10 · 6 + ___ = 10 = 4 · 6 + ___ = 17 = 11 · 10 + ___ = 16 = 6 · 6 + ___ = 8 = 2
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 Treehouse Camp Mystery — set in The Great Treehouse Camp
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects