# Introduction

For centuries, logarithm was used to simplify calculations. Before electronic electronic calculators became widely available, slide rule, logarithm-based mechanical calculator, was the symbol of the engineer’s profession.

# Introduction

In our previous article we talked about percents and how they are calculated in Solidity. In financial math percents are usually associated with interest being paid on loans and deposits. At the end of every time period, say one month or one year, a certain percent of the principal amount…

# Introduction

Financial math begins with percents. What is x percent of y? How much percent of x is y? We all know the answers: x percent of y is x×y÷100 and y is y×100÷x percent of x. This is school math.

# Introduction

Every time I see `+`, `*`, or `**` doing audit of another Solidity smart contract, I start writing the following comment: “overflow is possible here”. I need a few seconds to write these four words, and during these seconds I observe nearby lines trying to find a reason, why overflow…

# Introduction

Ethereum is a programmable blockchain, whose functionality could be extended by publishing pieces of executable code, known as smart contracts, into the blockchain itself. …