# Build a simple invoicing system

In this video we will show you how to build an invoicing system using the following features:

* [Sub Blocs](https://manual.blocworx.com/blocworx-documentation/bloc-editor/fields-tools-and-charts/sub-blocs-tools-components/sub-bloc)
* [Maths Fields](https://manual.blocworx.com/blocworx-documentation/bloc-editor/fields-tools-and-charts/dynamic-output-and-variable-components/maths-field)
* [Some total calculation rules](https://manual.blocworx.com/blocworx-documentation/bloc-editor/managing-a-field/field-rules/populate-another-local-field-with-total-from-elsewhere)
* [Our Template Builder](https://manual.blocworx.com/blocworx-documentation/bloc/pdf-and-doc-file-templates)

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