No.
3/7
Yes, 21/3 = 7/1
3/7 (3 over 7) cannot be simplified nor can 4/7 (4 over 7)
7/3
It is 7 over 3, or 2 and 1 over 3.
The fraction 7/3 cannot be reduced any more.
3/7
3/7
3 and 4/7 cannot be reduced further.
7 over 10 can not be reduced!
27 over 7 equals 3 and 6 sevenths