You're developing a functionality to manage transactions for an insurance company.

You're developing a functionality to manage transactions for an insurance company. Each transaction can have multiple items where respective item type and item amount can be entered. The amount entered can be either negative or positive, and is a decimal data type with a precision of 8 and a scale of 2.

A maximum of 10 items can be entered for a transaction. Once all the items are entered, you need to calculate and show the sum of all items' total amounts at the transaction level.

What is the best way to calculate and display the sum of all item amounts?