It cannot be reduced any further, therefore its stays as 19/21
13/21 can't be reduced.
21/40 cannot be reduced.
19/10 is reduced and the answer is 1 and 9/10
25/21 is already reduced to its lowest terms
19/21 - 2/7 = 19/21 - 6/21 = 13/21
No.
18 over 38 reduced = 9/19
736 and 21 are comprime so the fraction cannot be reduced.
No.
Yes, 21/3 = 7/1
22 over 38 can be reduced by dividing both the numerator and denominator by their greatest common factor, which is 2. Therefore, 22 over 38 reduced is 11 over 19.