![dapp-a-day-25 2x](https://cloud.githubusercontent.com/assets/6280810/18453511/f0734c5e-793f-11e6-9ee2-0123dd2717bc.png)

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Today we are going to explore the RLP structure, which we are going to use to build an naive implementation of an in-memory calculator. Imagine you produce expressions S-expressions like `(* (+ 1 2) (+ 1 2))`. Wouldn't it be great to just pass this expression to some contract and receive 9 as a return? Well this example shows you how to approach something line this. The main focus of this however, is to teach you [RLP](https://github.com/ethereum/wiki/wiki/RLP), one of the core technologies which drives Ethereum.


### https://github.com/nexusdev/rlp-calculator

**You can explore RLP also with [this](https://www.npmjs.com/package/rlp) package.**