How Ancient Egyptians Shaped Fractions, Decimals & Percentages

Ever wondered why ⅓ turns into a never-ending decimal or why sales tax feels oddly specific? Fractions, decimals and percentages are three sides of the same mathematical coin—but their story starts millennia ago. We’ll explore how these number formats evolved, why they still trip us up, and where you’ll bump into them every day.

Where did this come from?

Thousands of years ago, Egyptian scribes recorded all fractions (except ½) as sums of distinct unit fractions (like ⅓ + ⅙ + ⅒). The Rhind Mathematical Papyrus (around 1650 BCE) shows how they solved problems with this quirky system. Fast-forward to the 16th century: Flemish mathematician Simon Stevin introduced decimals to Europe, making calculations with tenths and hundredths far easier. Around the same time, Italian merchants popularised “per centum” (percent) for taxes and trade, giving us the 100-based way to describe parts of a whole.

Where you’ll see this in real life

1. Shopping discounts and markups: 25% off or a 15% profit margin are everyday uses of percentages. 2. Cooking and baking: Recipes often ask for ¾ cup or 0.75 litre—switching between fractions and decimals helps you scale ingredients. 3. Finance and interest rates: Banks quote interest as percentages (e.g., 3.5% per annum), but loan amortisation relies on decimal models beneath the hood. 4. Data and media: File compression ratios and success rates (say, 0.9 or 90%) guide decisions in tech and quality control.

A common misconception

A lot of students think adding percentages is straightforward—if a price goes up by 10% then down by 10%, you’re back where you started. In reality, a 10% drop after a 10% rise doesn’t cancel out because the base amount changed. That little twist arises from how percentages link back to different starting values.