21
the answer is 21.
3 / 1/7 = 3 x 7 = 21 Therefore, there are 21 sevenths in three wholes.
3/7 x 21 = 9
21
7
make the lower number the same 3/7 x 8/8 = 24/56 3/8 x 7/7 = 21/56 so three sevenths is bigger
20/21
49
Expressed as a mixed number in its simplest form, 30/21 is equal to 1 3/7 or one and three sevenths.
If: 3x = 21 then x = 7
21 over 8