How to add or subtract the values of two panels on a page.

How to add or subtract the values of two panels on a page.

I have created a Page and there are two panels there showing some values from two different Forms.
(They show the Sum of the forms as number.)

I want a third panel that will show the subtract of these two panels.
It might sound easy, but I can't find a way to do it.
Can I get some hints please?
    Zoho Marketing Automation
      Zoho Mail - CRM Integration

              Zoho Pagesense Resources

                Zoho SalesIQ Resources



                      Zoho TeamInbox Resources

                        Zoho DataPrep Resources



                          Zoho CRM Plus Resources

                            Zoho Books Resources


                              Zoho Subscriptions Resources

                                Zoho Desk Resources

                                  Zoho Projects Resources


                                    Zoho Sprints Resources


                                      Qntrl Resources


                                        Zoho Creator Resources


                                          Zoho WorkDrive Resources




                                              Zoho Campaigns Resources

                                                Zoho CRM Resources

                                                        Design. Discuss. Deliver.

                                                        Create visually engaging stories with Zoho Show.

                                                        Get Started Now