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Math Gym
Addition Guide

Addition Level 15: 3d + 2d (mastery). answer-window addition.

1. Fill hundreds

Step 1: Fill hundreds
raw windows
running strip
Hundreds window: 7 + 0 = 7. Hold 7; wait for carry from the next window.

2. Fill tens

Step 2: Fill tens
raw windows
running strip
Tens window: 8 + 9 = 17. Hold raw 17; settle carry later.

3. Fill ones

Step 3: Fill ones
raw windows
running strip
Ones window: 6 + 5 = 11. Hold raw 11; settle carry later.

4. Settle carry

Step 4: Settle carryKeep ones; carry moves left.raw windows
settled digits
Settle raw 7 | 17 | 11 into 881; keep ones and move carry left.