26.)squareroot of 36divide by 2 (28.) 0 (30.)5.010010001...?

Question

classify each number in as many ways as possible?

Answer 1

26.) sqrt(36)/2 => 6/2 = 3, this is a positive real integer
26.) (alternate) sqrt(36/2) => 6/sqrt(2) => 6*sqrt(2)/2 => 3*sqrt(2) positive real irrational number

28.) 0 => zero, real number, integer, natural number (depending on your interpretation)

30.) 5.010010001 => repeating? rational real number
see http://mathforum.org/library/drmath/view/58106.html