Fractions, Decimals and Percentages: From Egyptians to Discounts

Ever stared at 3/4 on your worksheet, 0.75 on your calculator and 75% on a sale sign and wondered why they all feel so different? The truth is they’re just three ways of expressing the same slice of a whole. Understanding how fractions, decimals and percentages link gives you the power to tackle anything from cooking a recipe to spotting a clever retail trick.

Where did this come from?

The ancient Egyptians were one of the first cultures to record fractions around 1800 BC—but here’s the twist: they only wrote fractions with a numerator of 1, called unit fractions. So instead of writing 2/5, they’d write 1/3 + 1/15. Fast forward to the late 1500s and Flemish mathematician Simon Stevin popularised decimal fractions, making calculations much smoother. And the word “percent” comes from Latin per centum, meaning “per hundred,” a shorthand medieval Italian merchants used when trading goods.

Where you'll see this in real life

1. Grocery shopping: That 25% off sticker is a percentage, but you’re really taking a quarter (fraction) off the original price or moving the decimal two places in your head. 2. Cooking: Recipes often call for 3/8 of a cup or 0.375 L, and knowing the link between fractions and decimals helps you measure accurately. 3. Finance: Interest rates, loan repayments and savings growth all use percentages—turning fractions into decimals and vice versa helps you compare deals. 4. Tech and health: Your phone’s battery life, fitness tracker goals and fuel gauges on cars all display percentages or decimals to show how much of a full charge, step goal or tank you’ve used.

Tips for mastering conversions

• Fraction to decimal: divide numerator by denominator (e.g. 3 ÷ 4 = 0.75). • Decimal to percentage: multiply by 100 and add “%” (0.75 × 100 = 75%). • Percentage to decimal: remove “%” and divide by 100 (25% → 25 ÷ 100 = 0.25). • Decimal to fraction: write the number over its place-value (0.75 = 75/100) then simplify (75/100 = 3/4). Visual aids like pie charts or bar models can help you see the same quantity in three different ways. Practice small steps, and converting will feel like second nature!