<%
String a = (String)session.getAttribute("a"),
b = (String)session.getAttribute("b"),
message = (String)session.getAttribute("message");
if (message == null) {
a = (int)(Math.random() * 100 - 50) + "";
b = (int)(Math.random() * 100 - 50) + "";
message = "What is " + a + " + " + b + "?";
} else {
String answer = request.getParameter("answer");
int user = Integer.parseInt(answer);
if (Integer.parseInt(a) + Integer.parseInt(b) == user) {
message = "The answer was correct. ";
} else {
message = "Wrong answer.
";
}
a = (int)(Math.random() * 100 - 50) + "";
b = (int)(Math.random() * 100 - 50) + "";
message += "What is " + a + " + " + b + "?";
}
session.setAttribute("a", a);
session.setAttribute("b", b);
session.setAttribute("message", message);
%>
<%=message%>