# Session 6: Calculator

## Project description

In this project we have to implement a simple
calculator that supports these for operations:

* `+`: add
* `-`: substract
* `*`: multiply
* `/`: divide

Also we want to have history.
We want 10 history rows and we should
be able to switch between history rows using
`up` and `down` keys.
For more detail see the examples.

We also need a button that deletes a history
row.

* No need to supprot float numbers.
* You are free to come up with your own different keys,
  these key combinations are just for an example.
* You can add any number of keys that you want.
* Only need to support and operation between two numbers.

## Examples

### History up

![s6_history_up](figures/s6_history_up.gif)

### History down

![s6_history_down](figures/s6_history_down.gif)

### Delete

![s6_delete](figures/s6_delete.gif)

### Add

![s6_add](figures/s6_add.gif)

### Substract

![s6_substract](figures/s6_substract.gif)

### Multiply

![s6_multiply](figures/s6_multiply.gif)

### Divide

![s6_divide](figures/s6_divide.gif)