string="hello world";
StringQ[string]

number=1.5;
NumberQ[number]

StringQ[number]

NumberQ[string]

a=1;s="hello";
b=2;
c=a+b+s;
Print[c]

Do[
Print[n];
Print["Hello for the ", n , " times"];
Print[" "];
, {n,0,4,1}
];