4/3 can also be written 8/6 which makes it easier to do the arithmetic.
8/6-1/6=7/6, same as 1⅙;
8/6+1/6=9/6=3/2, same as 1½.
For the multiplication leave 4/3 as it is:
4/3×1/6=⅔×⅓=2/9 (4 and 6 have the common factor, so divide each by 2).
4/3➗1/6=4/3×6=4×2=8 (because 3 goes into 6 2 times).