irrational number: cannot be expressed as a simple fraction
a. [tex]\tt 2-\sqrt{3}:irrational[/tex]
b. [tex]\tt \sqrt{2}\times \sqrt{3}=\sqrt{6}:irrational[/tex]
c. [tex]\tt \sqrt{27}\times \sqrt{3}=\sqrt{81}=9:rational[/tex]
d. [tex]\tt =0\sqrt{7}=0:rational[/tex]
