Subtract 7 ft 10 3/4 inches from 8 ft 0 inches:
8 ft 0 inches
- 7 ft 10 3/4 inches
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Since we cannot subtract 10 3/4 inches from 0 inches, borrow 12 inches (1 ft) from 8 ft 0 inches:
7 ft 12 inches
-7 ft 10 3/4 inches
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1 1/4 inches (answer)