# Formulas

Formulas are little utilities embedded in your notes. They work a lot like formulas in a spreadsheet without the need for a whole table.

Formulas can do standard math stuff like add and subtract numbers, they can get the value of a bean between two dates, and they can do lots of surprising things when combined with other Tap functions.

There are a few different categories of functions:

Each on their own are fairly abstract, but through combination their usefulness grows.

Here are a few examples:

``````\$\$()(+ 1 1)
``````

This adds 1 and 1 and renders "2" in our note

We can give the formula a name:

``````\$\$("Add one and one")(+ 1 1)
``````

This renders "Add one and one: 2" in our note

We can harness the power of the unknown using `random`.

``````\$\$("Roll of the dice")(random 1 6)
``````

We can flip a coin:

``````\$\$("The coin flipped")
(list-item
(random 0 1))
``````

That last one took a big leap, let's break it down.

``````\$\$()(list "heads" "tails")
``````

This will create a list with two items: "heads" and "tails". It will show up in the note as "heads, tails".

``````\$\$()(list-item (list "heads" "tails") 0) -> always renders "heads"
\$\$()(list-item (list "heads" "tails") 1) -> always renders "tails"
``````

By introducing chaos from the universe we will randomly select "heads" or "tails"

``````\$\$("The coin flipped")
(list-item