An eighth means that a whole of something is cut into eight pieces, parts or sections.
Therefore: 8 x 2 = 16 (or sixteen over eight)
Sixteen eights equal two thirds
Ten fifths make two wholes.
2/1 is the fraction equal to two wholes
Three twelfths is equal to one fourth, which is equal to two eights.
6, each whole is 3 thirds
There are two eights in one fourth.