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Math Gym
Subtraction Guide

Subtraction Level 30: 4d - 4d (mastery). borrow-window subtraction.

1. Release thousands

1. Release thousandsRelease one digit; only borrow stays active.
answer strip
Pay right borrow; release 4: 9 - 4 - 1 = 4.

2. Release hundreds

2. Release hundreds
answer strip
Borrow 10; pay right borrow: 10 - 6 - 1 = 3.

3. Release tens

3. Release tens
answer strip
Borrow 10; pay right borrow: 10 - 8 - 1 = 1.

4. Release ones

4. Release ones
answer strip
Borrow 10; release 8: 15 - 7 = 8.

5. Read answer

5. Read answerDrop finished digits; borrow is gone.
Read 4 | 3 | 1 | 8 as 4318; borrow is gone.