Select the Calculation Algorithm > Save main menu item.
Click the 
button on the quick access toolbar.
To work with the tool in Foresight Analytics Platform 10, use the new interface.
To save a calculation algorithm:
Select the Calculation Algorithm > Save main menu item.
Click the button on the quick access toolbar.
All changes in the calculation algorithm will be saved.
See also:
Getting Started with the Calculation Algorithms Extension in the Web Application | Building Calculation Algorithm