Yes, -1/6 is a real number
It is a rational number - it is a fraction or a terminating/repeating decimal if converted to decimal
Only Imaginary are not imaginary numbers, such as i=
Natural- counting numbers (no zero), Whole- no fraction or negatives, Integers- negative, Rational- fraction or terminating/repeating decimals, and Irrational numbers- non repeating decimals: are all real numbers