# Field Programmable Gate Array

So I’ve been playing with R(the software environment for statistical computing and graphics) this week as well as trying to learn C and I’ve been thinking about fun, real-world data/stuff to work with. Which of course leads to sets of data for R and programmable IC (Integrated Circuits) such as the ones found on development boards like the Raspberry Pi or Arduino or BeagleBoard etc.

I discovered Field Programmable Gate Array and now just need a reason to order a Breadboard. Wifi enabled motion detection system for the meeting rooms at work (they’re always booked and seldom used). Dunno.

While reading up on programming chips I found out that a common way for computers to deal with subtraction using addition!

This method is called the Method of Complements and it’s really easy.

```
5678
- 3493 <- You want to subtract 3493 from 5678.
----
5678
+ 6506 <- Get each digit that you're trying to subtract up to 9: 3 needs 6, 4 needs 5, 9 is already there so 0, 3 needs 6. = 6506
----
12184
-10000 <- Remove the trailing 1 (no actual subtraction required)
====
2184
+1 <- Add 1 to complete the magic!
====
2185
```

**Links to interesting pages:**

Building a Hacker News clone in Django - Part 1

Beth Scott is a pretty awesome engineer: Her UsersThis profile http://scanlime.usesthis.com/