Answer:
check your math
Step-by-step explanation:
The first subtraction was correct:
36 -7 3/4 = 28 1/4
The second subtraction needs to be revisited.
28 1/4 -6 2/4 = 27 5/4 -6 2/4 = 21 3/4
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You can do what you did, but you need to pay attention to the signs.
28 1/4 -6 2/4 = (28 -6) +(1/4 -2/4) = 22 - 1/4 = 21 3/4
The result of subtracting 2/4 from 1/4 is -1/4, not +1/4.
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The length of the first cut piece was 21 3/4 inches.