Quest Key Guide
Navigator Map
Answer Key & Strategy Guide
TEACHER ONLY
Objective
Students will solve subtraction word problems within 100 by visualizing subtraction as distance or removal on a linear number line.
Key Strategy
Encourage "Jump Back" (Tens then Ones) for large subtractions and "Jump Up" (Find the Difference) for close numbers.
Problem 1
Acorns Problem
72 - 25 = 47
Suggested Steps (Jump Back):
- Start at 72.
- Jump back 20 (72 → 52).
- Jump back 5 (52 → 47).
Problem 2
Eagle Scout Hike
85 - 78 = 7
Suggested Steps (Jump Up/Gap):
- Start at 78 (the smaller number).
- Jump 2 to reach 80 (the next ten).
- Jump 5 more to reach 85.
- Total difference = 2 + 5 = 7.
Problem 3
Benny's Dam Sticks
94 - 46 = 48
Suggested Steps:
- Start at 94.
- Jump back 40 (94 → 54).
- Jump back 6 (54 → 48).
Beyond the Trail
Extension Activity
Trail Mix Subtraction: Give students a handful of snacks. Have them estimate the total, then "remove" chunks (subtract) and use a desk-length tape number line to model the removal.
Critical Questioning
"When would it be faster to count up from the smaller number instead of jumping back from the larger one? Can you find a problem on your page where counting up felt easier?"
Deep Dive: Misconception Check
Directionality: Ensure students understand that subtraction moves to the left on the line. When "finding the gap," emphasize that although we move right to count, the total distance represents the subtraction result.
