Question 728149
Please help.

7/8 - 9/20
Find a common denominator.
The product always works, 8*20 = 160

7/8 - 9/20 = 140/160 - 720/160 = - 580/160
= -29/8
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7 1/3- 4 5/12
Change to improper fractions
7 1/3- 4 5/12 = 22/3 - 53/12
Do it like the 1st one.
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9 2/5- 1 1/4
Same as the 2nd one.