If you mean 21/28 then it is 3/4
The reduced fraction of 28/32 is 7/8
The reduced fraction for 21/30 is 7/10
21/12 as a reduced fraction = 1.75
21/40 cannot be reduced.
0.7
21/40 cannot be reduced.
28% or 0.28 = 7⁄25
2/7 is the most reduced fraction but other equivalent fractions would be... 4/14 6/21 8/28 10/35 12/42 etc...
48
28% = 28/100 = 7/25
736 and 21 are comprime so the fraction cannot be reduced.
The fraction 19/21 cannot be reduced any more.