how to sum two field

[abasakre]

• Laravel Version: #.#.#
• Nova Version: #.#.#
• PHP Version: #.#.#
• Database Driver & Version:
• Operating System and Version: #.#
• Browser type and version: #.#
• Reproduction Repository: https://github.com/###/###

Description:

how to sum to number like this

Demo

Detailed steps to reproduce the issue on a fresh Nova installation: