Greetings!
"Add or subtract. Be sure to reduce your answer: 5\6-9/20"...
To add or subtract rationals, you must find a common denominator of both fractions.
This can be done by multiplying the denominators by each other:
6*20=120
We must do the same operation to the numerators.
5*20=100
9*6=54
Now we can the subtract the rationals:
100/120-54/120
=100-54/120
=46/120
=23/60
Hope this helps.
-Benjamin