private void butSingleCalculat_Click(object sender, EventArgs e)
        {
            SystemConstants.SingleCalcultGrade = (int)numericUpDown1.Value;

            FrmSingleGradeCalculate childFrame = new FrmSingleGradeCalculate();
            childFrame.Show();
            this.Close();
        }
        private void butSingleCalculat_Click(object sender, EventArgs e)
        {
            SystemConstants.SingleCalcultGrade = (int)numericUpDown1.Value;

            FrmSingleGradeCalculate childFrame = new FrmSingleGradeCalculate();

            childFrame.Show();
            this.Close();
        }