2 5/8oz if you use a thrid of it how much is she gone have left over

Lets convert the fraction first to ease the calculations:

2 5/8 = 16/8 + 5/8 = 21/8

so now we can operate easily, to calculate we need to multiply 21/8 by 2/3 that is because, if 1/3 is used then 2/3 are left over (1/3 + 2/3 = 1, the total), so we have:

(2/3) (21/8) = (2*21) / (3*8)

= 42/24

= 21/12

= 7/4

so 7/4 are left over