Grid Hopper Worksheet
100
GRID HOPPER
Hundred Chart Addition & Subtraction (Within 50)
Name:
Date:
Hundred Chart (1–100) Touch and hop to solve!
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Chart Hop Rules
↑
Hop Up
− 10 (subtract)
↓
Hop Down
+ 10 (add)
←
Hop Left
− 1 (subtract)
→
Hop Right
+ 1 (add)
Hop Strategy Example
To solve 23 + 14:
- Start at number 23.
- Hop down 1 row (+10) to 33.
- Hop right 4 spaces (+4) to 37.
23 + 14 = 37
- Part 1: Addition Within 50 Hop down for tens, hop right for ones
1 21 + 14 =
2 15 + 23 =
3 32 + 15 =
4 18 + 20 =
5 26 + 18 =
6 34 + 13 =
− Part 2: Subtraction Within 50 Hop up for tens, hop left for ones
7 45 − 12 =
8 38 − 20 =
9 49 − 24 =
10 32 − 14 =
11 50 − 21 =
12 43 − 16 =
Part 3: Grid Detective Challenges Track the hops on your chart
A Mystery Number Hop
Start at 14. Hop down 2 rows (+20). Hop right 3 squares (+3). Where are you?
Number:
B Word Problem Hop
Liam had 46 stickers. He gave 18 stickers to his friend. Use the chart to solve: 46 − 18
Left:
Strategy Tip: Check your work by reversing your hops!
Total Score: _____ / 14
Grid Hopper Answer Key
GRID HOPPER
Answer Key
Hundred Chart Addition & Subtraction (Within 50)
Assessment Scale 14 Questions • 1 pt each
Hop Rule Key:
↓ Down = +10 ↑ Up = −10 → Right = +1 ← Left = −1
Students may hop tens first or ones first.
- Part 1: Addition Within 50 (Answers & Pathways) 6 Points
1 21 + 14 =
21 ↓10 (31) →4
35
2 15 + 23 =
15 ↓20 (35) →3
38
3 32 + 15 =
32 ↓10 (42) →5
47
4 18 + 20 =
18 ↓20 (2 rows down)
38
5 26 + 18 =
26 ↓10 (36) →8 (or +20, −2)
44
6 34 + 13 =
34 ↓10 (44) →3
47
− Part 2: Subtraction Within 50 (Answers & Pathways) 6 Points
7 45 − 12 =
45 ↑10 (35) ←2
33
8 38 − 20 =
38 ↑20 (2 rows up)
18
9 49 − 24 =
49 ↑20 (29) ←4
25
10 32 − 14 =
32 ↑10 (22) ←4 (cross row)
18
11 50 − 21 =
50 ↑20 (30) ←1
29
12 43 − 16 =
43 ↑10 (33) ←6
27
Part 3: Grid Detective Challenges 2 Points
A Mystery Number Hop
Start at 14. Down 2 rows (+20) = 34. Right 3 squares (+3) = 37.
Equation: 14 + 20 + 3 = 37
Answer:
37
B Word Problem Hop
Start at 46 stickers. Give away 18: Up 1 row (−10) = 36. Left 8 squares (−8) = 28.
Equation: 46 − 18 = 28
Answer:
28
Teacher Diagnostic Notes & Common Misconceptions
Crossing Decades (Row Boundaries):
In problems like #10 (\(32 - 14\)) or #5 (\(26 + 18\)), students must jump across row ends (e.g., jumping left from 21 leads to 20 at the far right of the row above). Guide students to count continuously on the chart.
Inverted Vertical Hops:
Young learners sometimes associate "Up" with addition. Emphasize that numbers increase downward on a standard hundred chart: Down is +10 (numbers get larger), Up is −10 (numbers get smaller).
