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Addition

Level 30 / mastery

4d + 4d (mastery)

5 visual steps / large answer-window addition

1. Fill thousands

Step 1: Fill thousands
raw windows
running strip
Thousands window: 7 + 9 = 16. Hold raw 16; carry settles later.

Thousands window: 7 + 9 = 16. Hold raw 16; carry settles later.

2. Fill hundreds

Step 2: Fill hundreds
raw windows
running strip
Hundreds window: 8 + 2 = 10. Hold raw 10; settle carry later.

Hundreds window: 8 + 2 = 10. Hold raw 10; settle carry later.

3. Fill tens

Step 3: Fill tens
raw windows
running strip
Tens window: 6 + 8 = 14. Hold raw 14; settle carry later.

Tens window: 6 + 8 = 14. Hold raw 14; settle carry later.

4. Fill ones

Step 4: Fill ones
raw windows
running strip
Ones window: 5 + 7 = 12. Hold raw 12; settle carry later.

Ones window: 5 + 7 = 12. Hold raw 12; settle carry later.

5. Settle carry

Step 5: Settle carry
Settle onceKeep ones; carry moves left.raw windows
settled digits
Settle raw 16 | 10 | 14 | 12 into 17152; keep ones and move carry left.

Settle raw 16 | 10 | 14 | 12 into 17152; keep ones and move carry left.

Practice Level 30

A few quick rounds make digit release automatic; carry is the only thing to keep.

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