Grade 1Reading: grades 1-2Skip countingAdditionSubtractionPlace valueMissing addends
The Great Treehouse Mystery
Someone snuck into Treehouse Valley and took the master map! Work with the Jungle Patrol to solve the math clues and stop the bandit.
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 | Gear | Badge | Handedness | Hair Color | Weakness |
|---|---|---|---|---|---|
| Aria | Zip Line | Golden Star | Right Handed | Red Hair | Snap Photo |
| Ruby | Flash Bomb | Golden Star | Left Handed | Red Hair | Loud Whistle |
| Lucy | Smoke Bomb | Silver Moon | Right Handed | Red Hair | Loud Whistle |
| Jack | Grappling Hook | Ruby Shield | Left Handed | Black Hair | Loud Whistle |
| Leo | Grappling Hook | Bronze Sun | Left Handed | Black Hair | Bright Light |
| Liam | Grappling Hook | Silver Moon | Left Handed | Black Hair | Bright Light |
| Finn | Flash Bomb | Emerald Gem | Right Handed | Brown Hair | Snap Photo |
| Emma | Smoke Bomb | Golden Star | Left Handed | Black Hair | Snap Photo |
| Max | Zip Line | Silver Moon | Left Handed | Red Hair | Snap Photo |
| Noah | Zip Line | Ruby Shield | Right Handed | Brown Hair | Loud Whistle |
| Zoe | Grappling Hook | Emerald Gem | Right Handed | Brown Hair | Loud Whistle |
| Isla | Zip Line | Bronze Sun | Left Handed | Black Hair | Bright Light |
| Nora | Flash Bomb | Emerald Gem | Left Handed | Red Hair | Bright Light |
| Ava | Zip Line | Ruby Shield | Left Handed | Black Hair | Bright Light |
| Maya | Flash Bomb | Bronze Sun | Left Handed | Black Hair | Bright Light |
| Owen | Grappling Hook | Ruby Shield | Left Handed | Black Hair | Bright Light |
| Chloe | Zip Line | Ruby Shield | Right Handed | Black Hair | Bright Light |
| Luke | Zip Line | Ruby Shield | Left Handed | Red Hair | Snap Photo |
| Eli | Zip Line | Golden Star | Right Handed | Black Hair | Snap Photo |
| Sam | Glider Wings | Silver Moon | Left Handed | Black Hair | Bright Light |
| Kai | Smoke Bomb | Silver Moon | Right Handed | Black Hair | Loud Whistle |
Clue 1
Skip counting
We need to count steps along the jungle trail by twos to follow the footprints.
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
45
26
80
18
9
25
25
60
9
65
110
24
80
6
65
24
T
45
26
60
18
80
60
8
27
24
65
42
80
6
12
65
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, 9, 12, 15, 18, 21, ___, 27, 30O
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, ___, 70, 80A
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, ___, 30, 33R
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, ___, 28, 30H
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, ___, 45, 48Z
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, ___, 120, 130D
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75N
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, ___, 90, 100E
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35L
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, ___, 20, 22V
Skip-count by 3s. Fill the blank: 3, 6, ___, 12, 15I
Skip-count by 2s. Fill the blank: 2, 4, 6, ___, 10, 12B
Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10S
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16U
0/15 letters found
Clue 2
Addition
We add up all the shiny camp pins we found near the treehouse.
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
15
20
4
8
18
T
15
11
4
17
17
17
3
8
3
13
4
10
T
15
20
3
11
12
4
12
9
3
11
12
18
T
15
11 + 4 =T
5 + 5 =F
2 + 1 =A
3 + 1 =E
9 + 4 =L
7 + 2 =B
6 + 11 =S
3 + 8 =N
9 + 9 =I
4 + 8 =D
6 + 2 =W
13 + 7 =H
0/12 letters found
Clue 3
Subtraction
We take away the cracked mud tiles to see what is underneath.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
F
2
16
1
11
5
14
16
4
9
F
2
F
2
19
15
5
14
18
13
8
15
7
14
5
17
15
7
14
5
5 - 3 =F
9 - 4 =T
18 - 7 =D
19 - 2 =L
18 - 9 =O
19 - 3 =E
20 - 1 =W
5 - 1 =M
9 - 2 =G
19 - 5 =H
17 - 9 =R
19 - 1 =A
19 - 6 =B
20 - 5 =I
9 - 8 =N
0/15 letters found
Clue 4
Place value
We look at tens and ones on the trail signs to read the hidden code.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
B
77
49
63
96
72
81
63
54
41
97
63
48
20
32
22
66
87
63
27
27
81
57
48
96
57
66
57
What number has 7 tens and 7 ones?B
What number has 6 tens and 3 ones?A
What number has 2 tens and 7 ones?T
What number has 3 tens and 2 ones?O
What number has 8 tens and 1 one?H
What number has 7 tens and 2 ones?K
What number has 4 tens and 9 ones?L
What number has 2 tens and 2 ones?U
What number has 9 tens and 6 ones?C
What number has 5 tens and 4 ones?I
What number has 9 tens and 7 ones?W
What number has 6 tens and 6 ones?N
What number has 4 tens and 8 ones?S
What number has 5 tens and 7 ones?E
What number has 8 tens and 7 ones?D
What number has 4 tens and 1 one?R
What number has 2 tens and 0 ones?F
0/17 letters found
Clue 5
Missing addends — the last clue
We find the missing number of gems needed to open the secret door.
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 + ___ = 7
4 + ___ = 10
4 + ___ = 16
9 + ___ = 10
9 + ___ = 19
2 + ___ = 13
7 + ___ = 9
10 + ___ = 17
9 + ___ = 18
2 + ___ = 6
10 + ___ = 18
Step 2 — cross out the sentence with each answer
1.The villain swung on the rope, then swiped the bronze sun.
2.The villain flashed a bright light, then stole the ruby shield.
3.The villain swung on the rope, then grabbed the silver moon.
4.The villain zipped down the wire, then swiped the bronze sun.
5.The villain glided over trees, then grabbed the silver moon.
6.The villain swung on the rope, then stole the ruby shield.
7.The villain flashed a bright light, then took the emerald gem.
8.The villain flashed a bright light, then snapped the golden star.
9.The villain dropped a smoke bomb, then grabbed the silver moon.
10.The villain dropped a smoke bomb, then snapped the golden star.
11.The villain swung on the rope, then snapped the golden star.
12.The villain zipped down the wire, then stole the ruby shield.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Great Treehouse Mystery
Culprit: Liam (Grappling Hook · Silver Moon · Left Handed · Black Hair · Bright Light)
- Clue 1 (Skip counting): "THE VILLAIN DOES NOT HAVE A BRONZE SUN"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, 9, 12, 15, 18, 21, ___, 27, 30 = 24 (O) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, ___, 70, 80 = 60 (A) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, ___, 30, 33 = 27 (R) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, ___, 28, 30 = 26 (H) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, ___, 45, 48 = 42 (Z) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, ___, 120, 130 = 110 (D) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75 = 65 (N) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, ___, 90, 100 = 80 (E) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35 = 25 (L) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, ___, 20, 22 = 18 (V) · Skip-count by 3s. Fill the blank: 3, 6, ___, 12, 15 = 9 (I) · Skip-count by 2s. Fill the blank: 2, 4, 6, ___, 10, 12 = 8 (B) · Skip-count by 2s. Fill the blank: 2, 4, ___, 8, 10 = 6 (S) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16 = 12 (U)
- Clue 2 (Addition): "THE WITNESS SAW A LEFT HANDED BANDIT"11 + 4 = 15 (T) · 5 + 5 = 10 (F) · 2 + 1 = 3 (A) · 3 + 1 = 4 (E) · 9 + 4 = 13 (L) · 7 + 2 = 9 (B) · 6 + 11 = 17 (S) · 3 + 8 = 11 (N) · 9 + 9 = 18 (I) · 4 + 8 = 12 (D) · 6 + 2 = 8 (W) · 13 + 7 = 20 (H)
- Clue 3 (Subtraction): "FEND THEM OFF WITH A BRIGHT LIGHT"5 - 3 = 2 (F) · 9 - 4 = 5 (T) · 18 - 7 = 11 (D) · 19 - 2 = 17 (L) · 18 - 9 = 9 (O) · 19 - 3 = 16 (E) · 20 - 1 = 19 (W) · 5 - 1 = 4 (M) · 9 - 2 = 7 (G) · 19 - 5 = 14 (H) · 17 - 9 = 8 (R) · 19 - 1 = 18 (A) · 19 - 6 = 13 (B) · 20 - 5 = 15 (I) · 9 - 8 = 1 (N)
- Clue 4 (Place value): "BLACK HAIR WAS FOUND AT THE SCENE"What number has 7 tens and 7 ones? = 77 (B) · What number has 6 tens and 3 ones? = 63 (A) · What number has 2 tens and 7 ones? = 27 (T) · What number has 3 tens and 2 ones? = 32 (O) · What number has 8 tens and 1 one? = 81 (H) · What number has 7 tens and 2 ones? = 72 (K) · What number has 4 tens and 9 ones? = 49 (L) · What number has 2 tens and 2 ones? = 22 (U) · What number has 9 tens and 6 ones? = 96 (C) · What number has 5 tens and 4 ones? = 54 (I) · What number has 9 tens and 7 ones? = 97 (W) · What number has 6 tens and 6 ones? = 66 (N) · What number has 4 tens and 8 ones? = 48 (S) · What number has 5 tens and 7 ones? = 57 (E) · What number has 8 tens and 7 ones? = 87 (D) · What number has 4 tens and 1 one? = 41 (R) · What number has 2 tens and 0 ones? = 20 (F)
- Clue 5 (Missing addends): surviving statement (box 3) → Liam2 + ___ = 7 = 5 · 4 + ___ = 10 = 6 · 4 + ___ = 16 = 12 · 9 + ___ = 10 = 1 · 9 + ___ = 19 = 10 · 2 + ___ = 13 = 11 · 7 + ___ = 9 = 2 · 10 + ___ = 17 = 7 · 9 + ___ = 18 = 9 · 2 + ___ = 6 = 4 · 10 + ___ = 18 = 8
About this mystery
- Grade level
- Grade 1 math
- Math topics
- Skip counting, Addition, Subtraction, Place value, Missing addends
- Reading level
- grades 1-2
- Theme
- The Great Treehouse Mystery — set in Treehouse Valley
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects