class Worksheet {

    private String title;
    private int numOfProblems;
    private int grade;

    public Worksheet() {
        title = "Math";
        numOfProblems = 0;
        grade = 100;
    }

    public String toString(){
        return title + " had " + numOfProblems + " problems. Grade: " + grade;
    }

    public void addProblems(int numOfProblems) {
        this.numOfProblems += numOfProblems;
    }

    public void changeTitle(String title) {
        this.title = title;
    }

}