Everyday math

A bowl of flour with a metal scoop, brass measuring cups and a digital kitchen scale arranged on a worktop, seen from above.

Cups to grams: the cooking conversion guide

Cups measure volume, grams measure weight. The conversions for flour, sugar, butter, and more — plus why flour is the tricky one.

A birthday cake covered with dozens of lit candles, photographed in a dark room so the flames stand out.

How to calculate exact age (years, months, days)

Why subtracting birth years fails on birthdays, and the three-step months-and-days math that gives an exact age.

A schoolboy writes in a notebook at his classroom desk with a worried look, while classmates work at desks behind him.

How to calculate GPA (weighted vs unweighted)

The 4.0 scale, credit-hour weighting, and the +1.0 weighted bump — with worked examples and what colleges actually check.

Fifteen round wall clocks arranged in neat rows each show a different time, like zone clocks used when converting times worldwide.

How to convert time zones without messing up meetings

UTC offsets, daylight saving traps, and the date line — plus the invite etiquette that stops 3am meetings before they happen.

A close-up of an outdoor thermometer shows its temperature scale against a blurred green background on a bright day outside.

How to Convert Celsius to Fahrenheit: Formula, Chart and Examples

Convert Celsius to Fahrenheit with the exact formula for both directions, the double-and-add-30 shortcut and its real error, a full chart and examples.

A stone path climbs a steep grassy hill under a warm sunset sky, the kind of incline whose steepness a slope calculation describes.

How to Calculate Slope From Two Points: Formula, Examples and Types

How to calculate slope from two points using the rise-over-run formula: all four slope types, worked examples, and parallel and perpendicular lines.

A hairpin bend climbs a steep cliff road above the clouds, the kind of incline that slope, gradient and grade all describe.

Slope vs Gradient vs Grade: What Is the Difference?

Slope, gradient and grade all mean rise over run, but each field uses its own word and format. Definitions, a full conversion table and the percent trap.

A yellow falling-rocks warning sign stands beside a steep rocky mountainside above a winding road in a high valley.

What Does a 100% Slope Mean? Why It Is 45 Degrees, Not Vertical

A 100% slope means rise equals run: a 45° angle, not a vertical wall. Why percent slope is unlimited, with ramps, roads, stairs and ski runs compared.

A school student writing in an open maths workbook at a desk, with exercises and small diagrams printed on the page.

Exponent Rules Explained: Zero, Negative and Fractional Powers

Exponent rules explained with worked examples: product, quotient and power rules, zero and negative exponents, fractional powers and classic sign errors.

A teacher leads a maths lesson while pupils raise their hands in a classroom decorated with numbers, where averages first appear.

Mean, Median and Mode: Differences, Examples and When to Use Each

Learn how mean, median and mode differ, with sorted worked examples, the salary outlier lesson, and a simple rule for choosing the right average.

A student writes in a spiral notebook with a pencil at a study desk, a calculator nearby, working through a maths problem.

How to Find the Vertex of a Parabola: Formula, Graph and Examples

Find any parabola's vertex with h = -b/(2a): worked examples, completing the square, the axis of symmetry and a projectile peak problem solved.