In this section, you will find a step by step to use the formula aggregation concept.

## Objective

Create a formula on Ritchie that will execute another formula inside it.

You’ll find all the informations you need in the how to group formulas tutorial section.

The idea is to group at least 2 formulas inside another one:

• `rit math sum numbers` (Level 1)
• `rit math multiply numbers` (TODO)

## Inputs

This formula needs to contain (at least) those three inputs parameters:

1. Number one (`RIT_UMBER_ONE`).
2. Number two (`RIT_NUMBER_TWO`).
3. Operation (`RIT_OPERATION`).

## Step by step

To implement this formula, it will be necessary to follow the steps below:

Premisse: Creation of the `rit math multiply numbers` formula (same as level 1).

1. Extract all inputs parameters.
2. Run the grouped formula according to the selected operation:
• multiply should call `rit math multiply numbers`
• sum should call `rit math sum numbers`
3. Return the result on the terminal.

## Improvement suggestions

If you want to play a little more, here are some suggestions: