B Turkey Run State Park Trail Hike
Difference / Remaining
Park rangers measured Trail 3 at 500 meters long. The nature club has already hiked 326 meters to the suspension bridge. How many meters do they have left to reach the trail end?
1. Fill in Tape Diagram:
Total Trail: 500 m
Hiked: 326 m
Left: [ ? ]
2. Solve:
_ _ _
5 0 0
- 3 2 6
Complete Statement: The club has ____________________ meters left to hike to reach the trail end.
C Indiana County 4-H Fair • 2-Step Challenge
Multi-Step
Maya scored 215 points and her brother Lucas scored 148 points at the livestock show. To win the county trophy, a team needs 500 points. How many more points do Maya and Lucas need together to win the trophy?
Step 1: Combine Points (Maya + Lucas)
Step 2: Find Remaining to 500
Complete Statement: Together, Maya and Lucas need ____________________ more points to win the trophy.
Cadet Self-Check:
I bundled 10 ones into 1 ten I unbundled across 0 correctly I labeled my story answers
Common Computation Pitfalls & Immediate Prescriptive Moves
Glitch 1: Upside-Down Subtraction (\(532 - 186 = 454\)) Frequency: High
What student does: Subtracts smaller top digit from larger bottom digit (\(6 - 2 = 4\)).
Prescription: Hand student 2 counters. Say: "Give me 6 counters." When student says "I can't!", state: "Exactly. You cannot take 6 from 2 without regrouping. Knock next door."
Glitch 2: The Zero Leapfrog (\(503 - 268 \rightarrow\) borrows 100 straight to ones) Frequency: Very High
What student does: Crosses out 5 to make 4, skips tens column, and makes 3 into 13, leaving 0 in tens untouched.
Prescription: Enforce the 2-step hop: "You cannot jump over your neighbor's house! Hundreds must unpack into tens (10 tens) first; then tens unpack into ones (leaving 9 tens)."
Glitch 3: The Forgotten Bundle in Addition (\(486 + 379 = 755\) or \(855\)) Frequency: Moderate
What student does: Calculates \(6 + 9 = 15\), writes 5, but forgets to write or add the carried ten into the tens column.
Prescription: Require the "Top-First Rule": Always add the small carried digit at the top before adding the other two numbers (\(1 + 8 = 9\), then \(9 + 7 = 16\)).
Glitch 4: "More Means Add" Story Problem Trap Frequency: High
What student does: Reads "How many more visitors..." and automatically adds \(612 + 385\).
Prescription: Use comparison tape diagram. "Who had more? Saturday. Draw a longer bar. Sunday had less. The question asks for the empty gap between the bars. A gap is a difference = SUBTRACTION!"
Tier 2 Questioning Stems to Prompt Self-Correction
For Computation:
For Story Problems:
Tiered Accommodations & Multi-Language Learner (ML) Support
Tier 3 Intensive: Keep base-ten blocks on desk during all calculations. Color-code ones (yellow), tens (blue), and hundreds (green) columns.
ML / ELL Scaffolding: Provide visual bilingual word cards ("together" = whole / add; "how many left" = part / subtract). Pre-read story contexts with gestures.
Rapid Extension: Have early finishers write their own 2-step story problem involving school supplies or mileage between Indiana cities.
Indiana Academic Standard 3.CA.2 Intervention Framework Page 2 of 2 • Ready for Classroom Delivery
\(368 + 257 = 625\). Student must show carried 1 ten above tens column (\(8+7=15\)) and carried 1 hundred above hundreds column (\(1+6+5=12\)).
Error Flag: If student writes 515 or 615, target the carried digits.
Item 2: Zero Unbundle 224 (1 Pt)
\(403 - 179 = 224\). Renaming steps: 4 hundreds \(\rightarrow\) 3; 0 tens \(\rightarrow\) 10 tens \(\rightarrow\) 9 tens; 3 ones \(\rightarrow\) 13 ones. \(13-9=4\); \(9-7=2\); \(3-1=2\).
Error Flag: 376 or 336 indicates upside-down subtraction.
Item 3: Story Problem 235 books (1 Pt)
\(420 - 185 = 235\). Full credit requires both correct numerical difference (235) and correct context label ("books"). Tape diagram must show 420 as whole and 185 as known part.
Error Flag: Adding \(420 + 185 = 605\) indicates failure to decode context.
Item 4: Error Spotter 257 (1 Pt)
Mistake Explanation: Marcus subtracted the top digits from bottom digits in ones (\(3-0=3\)) and tens (\(4-0=4\)) instead of regrouping.
Correct Calculation: \(500 - 243 = 257\).
Tier Intervention Decision Rules Post-Assessment Grouping
4 / 4 Mastered
Tier 1 Core Instruction Ready:
Student demonstrates solid conceptual and procedural command of 3.CA.2 within 1,000. Provide extension challenges (3-digit addition/subtraction with missing digits or multi-step perimeter problems).
3 / 4 Approaching
Targeted Mini-Intervention (10 Minutes):
Target the single isolated error. If Item 2 or 4 was missed, conduct a 10-minute "Zero Unbundle Station" using base-ten stampers or digital counters. If Item 3 was missed, reinforce the 3-Read tape diagram protocol.
0–2 / 4 Intensive
Tier 3 Intensive Intervention Required:
Step back on the CRA continuum to concrete manipulatives. Do not use standard algorithm grids until student can physically model trading 1 flat (100) for 10 rods (10s) and 1 rod for 10 units (1s) on a 3-column place value mat.
Indiana Academic Standard 3.CA.2 Master Diagnostic Guide Page 2 of 2 • Teacher Resource Document
