Create Maths Quiz in C# Windows Application

Random randomizer = new Random();
int addend1;
int addend2;
int timeLeft;
int minuend;
int subtrahend;
int multiplicand;
int multiplier;
int dividend;
int divisor;

private void timer1_Tick(object sender, EventArgs e)
        {
            if (CheckTheAnswer())
            {
                timer1.Stop();
                MessageBox.Show("You got all the answers right!",
                                "Congratulations");
                startButton.Enabled = true;
            }
            else if (timeLeft > 0)
            {
                timeLeft--;
                timeLeftLabel.Text = timeLeft + " seconds";
            }
            else
            {
                timer1.Stop();
                timeLeftLabel.Text = "Time's up!";
                MessageBox.Show("You didn't finish in time.", "Sorry");
                sum.Value = addend1 + addend2;
                difference.Value = minuend - subtrahend;
                product.Value = multiplicand * multiplier;
                quotient.Value = dividend / divisor;
                startButton.Enabled = true;

            }
        }

public void StartTheQuiz()
        {
            // Fill in the addition problem.
            addend1 = randomizer.Next(51);
            addend2 = randomizer.Next(51);
            plusLeftLabel.Text = addend1.ToString();
            plusRightLabel.Text = addend2.ToString();
            sum.Value = 0;

            // Fill in the subtraction problem.
            minuend = randomizer.Next(1, 101);
            subtrahend = randomizer.Next(1, minuend);
            minusLeftLabel.Text = minuend.ToString();
            minusRightLabel.Text = subtrahend.ToString();
            difference.Value = 0;

            // Fill in the multiplication problem.
            multiplicand = randomizer.Next(2, 11);
            multiplier = randomizer.Next(2, 11);
            multLeftLabel.Text = multiplicand.ToString();
            multRightLabel.Text = multiplier.ToString();
            product.Value = 0;

            // Fill in the division problem.
            divisor = randomizer.Next(2, 11);
            int temporaryQuotient = randomizer.Next(2, 11);
            dividend = divisor * temporaryQuotient;
            divLeftLabel.Text = dividend.ToString();
            divRightLabel.Text = divisor.ToString();
            quotient.Value = 0;

            // Start the timer.
            timeLeft = 60;
            timeLeftLabel.Text = "60 seconds";
            timer1.Start();
        }

private bool CheckTheAnswer()
        {
            if ((addend1 + addend2 == sum.Value)
                && (minuend - subtrahend == difference.Value)
                && (multiplicand * multiplier == product.Value)
                && (dividend / divisor == quotient.Value))
                return true;
            else
                return false;
        }

        private void startButton_Click(object sender, EventArgs e)
        {
            StartTheQuiz();
            startButton.Enabled = false;
        }