Grade 1Reading: grades 1-2AdditionSubtractionSkip countingPlace valueMissing addends
The Great Treehouse Caper
Someone took the Golden Banana Trophy from the Treehouse Club! The sneaky bandit left footprints in the mud. Help Explorer Toby find the bandit before the boat leaves the island.
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 | Escape Route | Dropped Item | First Step | Hair Style | Silly Weakness |
|---|---|---|---|---|---|
| Owen | Mud Slide | Shiny Compass | Right Foot First | Spiky Yellow Hair | Tickle Feather |
| Ryan | Mud Slide | Silver Whistle | Right Foot First | Straight Black Hair | Tickle Feather |
| Cole | Bridge Dash | Shiny Compass | Right Foot First | Straight Black Hair | Banana Peel |
| Noah | Zip Line | Silver Whistle | Right Foot First | Straight Black Hair | Water Splash |
| Ella | Rope Swing | Silver Whistle | Left Foot First | Straight Black Hair | Tickle Feather |
| Finn | Vine Climb | Shiny Compass | Right Foot First | Straight Black Hair | Water Splash |
| Emma | Bridge Dash | Spy Glass | Right Foot First | Curly Brown Hair | Water Splash |
| Ben | Bridge Dash | Golden Map | Left Foot First | Curly Brown Hair | Banana Peel |
| Cody | Rope Swing | Silver Whistle | Left Foot First | Spiky Yellow Hair | Tickle Feather |
| Toby | Vine Climb | Spy Glass | Right Foot First | Straight Black Hair | Banana Peel |
| Abby | Zip Line | Golden Map | Left Foot First | Straight Black Hair | Water Splash |
| Ava | Bridge Dash | Shiny Compass | Left Foot First | Straight Black Hair | Banana Peel |
| Jake | Vine Climb | Golden Map | Right Foot First | Straight Black Hair | Water Splash |
| Luke | Rope Swing | Shiny Compass | Left Foot First | Straight Black Hair | Water Splash |
| Sam | Mud Slide | Pocket Flashlight | Left Foot First | Spiky Yellow Hair | Tickle Feather |
| Jack | Zip Line | Shiny Compass | Right Foot First | Straight Black Hair | Banana Peel |
| Leo | Vine Climb | Silver Whistle | Left Foot First | Straight Black Hair | Tickle Feather |
| Max | Rope Swing | Shiny Compass | Right Foot First | Straight Black Hair | Water Splash |
| Lily | Rope Swing | Shiny Compass | Left Foot First | Curly Brown Hair | Tickle Feather |
| Kai | Bridge Dash | Pocket Flashlight | Right Foot First | Straight Black Hair | Tickle Feather |
| Zoe | Rope Swing | Spy Glass | Right Foot First | Straight Black Hair | Water Splash |
Clue 1
Addition
Toby counts the backpacks in the treehouse. We add the blue bags and red bags to find the total.
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
2
6
3
13
5
20
11
14
T
2
11
10
3
19
20
10
T
2
6
5
4
3
5
19
14
9
4
3
7
12
6
14
19
T
2
9
3
1 + 1 =T
3 + 1 =V
3 + 7 =O
6 + 14 =N
5 + 6 =D
5 + 8 =B
5 + 4 =L
2 + 4 =H
3 + 2 =A
5 + 9 =I
7 + 12 =S
5 + 2 =R
8 + 4 =W
1 + 2 =E
0/14 letters found
Clue 2
Subtraction
A monkey takes some bananas from our pile! Subtract the stolen bananas to see what is left.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
R
5
10
15
8
7
12
3
3
7
16
R
5
10
9
7
12
3
4
9
13
17
7
7
8
14
18
11
14
9
14
14 - 9 =R
18 - 2 =P
19 - 1 =S
14 - 7 =T
14 - 6 =H
19 - 7 =F
11 - 8 =O
16 - 7 =N
16 - 6 =I
18 - 4 =E
14 - 3 =C
19 - 2 =A
20 - 5 =G
19 - 6 =D
13 - 9 =U
0/15 letters found
Clue 3
Skip counting
We see footprints on the beach in groups of two. Let us count by twos to find the last step.
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
12
27
45
65
14
8
6
22
T
12
100
14
8
14
20
14
42
90
100
80
40
14
20
14
T
12
45
100
15
70
35
14
15
27
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16T
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, ___, 16, 18A
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, ___, 45, 48Y
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, ___, 75, 80P
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, ___, 22, 24W
Skip-count by 10s. Fill the blank: 10, 20, 30, ___, 50, 60M
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, ___, 24, 26I
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75B
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, ___, 30, 33H
Skip-count by 2s. Fill the blank: 2, 4, 6, ___, 10, 12N
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, ___, 90, 100O
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, ___, 110, 120R
Skip-count by 5s. Fill the blank: 5, 10, ___, 20, 25S
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45L
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55E
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110F
Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10D
0/17 letters found
Clue 4
Place value
Toby finds a secret map with gold coins. Count the tens and ones to read the gold number.
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
32
72
23
51
48
97
83
40
41
68
80
45
90
29
41
66
57
80
12
11
29
80
45
68
51
97
41
29
72
66
68
80
97
12
29
What number has 3 tens and 2 ones?W
What number has 5 tens and 7 ones?L
What number has 4 tens and 8 ones?U
What number has 9 tens and 0 ones?G
What number has 6 tens and 6 ones?B
What number has 5 tens and 1 one?O
What number has 2 tens and 9 ones?H
What number has 9 tens and 7 ones?N
What number has 2 tens and 3 ones?F
What number has 4 tens and 0 ones?S
What number has 4 tens and 1 one?T
What number has 7 tens and 2 ones?E
What number has 1 ten and 2 ones?C
What number has 4 tens and 5 ones?I
What number has 8 tens and 0 ones?A
What number has 8 tens and 3 ones?D
What number has 6 tens and 8 ones?R
What number has 1 ten and 1 one?K
0/18 letters found
Clue 5
Missing addends — the last clue
We need ten ropes to cross the swamp. We only have six. How many more do we need to make ten?
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
8 + ___ = 11
8 + ___ = 14
1 + ___ = 12
10 + ___ = 15
9 + ___ = 18
7 + ___ = 15
10 + ___ = 17
2 + ___ = 14
4 + ___ = 6
5 + ___ = 9
10 + ___ = 20
Step 2 — cross out the sentence with each answer
1.The villain swung on the rope, then lost a shiny compass.
2.The villain slid down the mud, then left a spy glass behind.
3.The villain swung on the rope, then left a spy glass behind.
4.The villain zipped down the line, then left a spy glass behind.
5.The villain dashed across the bridge, then dropped a golden map.
6.The villain climbed up the vine, then dropped a golden map.
7.The villain zipped down the line, then blew a silver whistle.
8.The villain slid down the mud, then dropped a pocket flashlight.
9.The villain dashed across the bridge, then dropped a pocket flashlight.
10.The villain slid down the mud, then lost a shiny compass.
11.The villain climbed up the vine, then lost a shiny compass.
12.The villain slid down the mud, then blew a silver whistle.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Great Treehouse Caper
Culprit: Max (Rope Swing · Shiny Compass · Right Foot First · Straight Black Hair · Water Splash)
- Clue 1 (Addition): "THE BANDIT DOES NOT HAVE A SILVER WHISTLE"1 + 1 = 2 (T) · 3 + 1 = 4 (V) · 3 + 7 = 10 (O) · 6 + 14 = 20 (N) · 5 + 6 = 11 (D) · 5 + 8 = 13 (B) · 5 + 4 = 9 (L) · 2 + 4 = 6 (H) · 3 + 2 = 5 (A) · 5 + 9 = 14 (I) · 7 + 12 = 19 (S) · 5 + 2 = 7 (R) · 8 + 4 = 12 (W) · 1 + 2 = 3 (E)
- Clue 2 (Subtraction): "RIGHT FOOTPRINT FOUND AT THE SCENE"14 - 9 = 5 (R) · 18 - 2 = 16 (P) · 19 - 1 = 18 (S) · 14 - 7 = 7 (T) · 14 - 6 = 8 (H) · 19 - 7 = 12 (F) · 11 - 8 = 3 (O) · 16 - 7 = 9 (N) · 16 - 6 = 10 (I) · 18 - 4 = 14 (E) · 14 - 3 = 11 (C) · 19 - 2 = 17 (A) · 20 - 5 = 15 (G) · 19 - 6 = 13 (D) · 13 - 9 = 4 (U)
- Clue 3 (Skip counting): "THE BANDIT RAN AWAY FROM A WATER SPLASH"Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16 = 12 (T) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, ___, 16, 18 = 14 (A) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, ___, 45, 48 = 42 (Y) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, ___, 75, 80 = 70 (P) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, ___, 22, 24 = 20 (W) · Skip-count by 10s. Fill the blank: 10, 20, 30, ___, 50, 60 = 40 (M) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, ___, 24, 26 = 22 (I) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75 = 65 (B) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, ___, 30, 33 = 27 (H) · Skip-count by 2s. Fill the blank: 2, 4, 6, ___, 10, 12 = 8 (N) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, ___, 90, 100 = 80 (O) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, ___, 110, 120 = 100 (R) · Skip-count by 5s. Fill the blank: 5, 10, ___, 20, 25 = 15 (S) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45 = 35 (L) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55 = 45 (E) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110 = 90 (F) · Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10 = 6 (D)
- Clue 4 (Place value): "WE FOUND STRAIGHT BLACK HAIR ON THE BRANCH"What number has 3 tens and 2 ones? = 32 (W) · What number has 5 tens and 7 ones? = 57 (L) · What number has 4 tens and 8 ones? = 48 (U) · What number has 9 tens and 0 ones? = 90 (G) · What number has 6 tens and 6 ones? = 66 (B) · What number has 5 tens and 1 one? = 51 (O) · What number has 2 tens and 9 ones? = 29 (H) · What number has 9 tens and 7 ones? = 97 (N) · What number has 2 tens and 3 ones? = 23 (F) · What number has 4 tens and 0 ones? = 40 (S) · What number has 4 tens and 1 one? = 41 (T) · What number has 7 tens and 2 ones? = 72 (E) · What number has 1 ten and 2 ones? = 12 (C) · What number has 4 tens and 5 ones? = 45 (I) · What number has 8 tens and 0 ones? = 80 (A) · What number has 8 tens and 3 ones? = 83 (D) · What number has 6 tens and 8 ones? = 68 (R) · What number has 1 ten and 1 one? = 11 (K)
- Clue 5 (Missing addends): surviving statement (box 1) → Max8 + ___ = 11 = 3 · 8 + ___ = 14 = 6 · 1 + ___ = 12 = 11 · 10 + ___ = 15 = 5 · 9 + ___ = 18 = 9 · 7 + ___ = 15 = 8 · 10 + ___ = 17 = 7 · 2 + ___ = 14 = 12 · 4 + ___ = 6 = 2 · 5 + ___ = 9 = 4 · 10 + ___ = 20 = 10
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 Caper — set in Treehouse Island
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects