what number should be subtracted from -2/3 to get -1/6

what number should be subtracted from -2/3 to get -1/6

let the required number is x.

According to the question,

-2/3-x=-1/6

Or, -x=-1/6+2/3

Or, -x=(-1+4)/6

Or, -x=3/6

Or, -x=1/2

Or, x=-1/2

Required number=-1/2