function testAbs(iNum){
 var str;
 var num1 = Math.abs(iNum);
 var num2 = Math.abs(-iNum);
 if (num1 == num2) s = "Absolute value: " + iNum + "\nand\n";
 s += "Absolute value: -" + iNum + "\nare identical.";
 return(s);
}