Compound Interest Explained: Formula and 5 Real Examples
The compound interest formula worked through five examples: simple vs compound, compounding frequency and APY, the Rule of 72, monthly deposits and real 2026 rates.
Profit Margin vs Markup: Formulas, Examples and a Conversion Table
Margin divides profit by the price, markup divides it by the cost. Formulas, a conversion table, pricing to a target margin, discounts and break-even examples.
How Many Weeks and Working Days Are in 2027?
52 weeks plus a day: 2027 has 261 weekdays, 11 federal holidays and 250 working days. Monthly working days, 2,088 work hours, 53 Fridays and payday counts.
Hourly to Salary: What $15, $20 and $25 an Hour Is per Year
Hourly rate × 2,080 hours for full time: $15 = $31,200, $20 = $41,600, $25 = $52,000. Tables by month and paycheck, unpaid time off, overtime and 2027’s extra hours.
Pythagorean Theorem: Formula, Proof and Real-World Uses
a² + b² = c² with worked examples for the hypotenuse and a missing leg, Pythagorean triples, a picture proof, and real uses from ladders to roof rafters.
Celsius to Fahrenheit: Formula, Mental Shortcut and Conversion Charts
The exact formula both ways, a shortcut that is close enough for weather, why temperature changes convert differently, and oven, cooking and candy charts.
How to Convert a Decimal to a Fraction (Including Repeating Decimals)
The four-step method, simplifying with the greatest common factor, the algebra trick for repeating decimals, nearest-fraction rounding and an inch fraction chart.
How to Calculate Square Footage of a Room, House or Odd Shape
Length × width for simple rooms, how to split L-shapes, triangles, circles and trapezoids, feet-and-inches, square yards and meters, and how homes are measured.
How to Calculate a Percentage: Of a Number, Percent Change and Reverse Percentages
The three percentage formulas, percent increase and decrease, working back from a sale price, why +10% then -10% loses money, and percent vs percentage points.
How Many Tablespoons in a Cup? Kitchen Conversions for Cups, Ounces and Grams
16 tablespoons make a cup. Charts for spoons, cups, fluid ounces and quarts, grams per cup for 15 baking ingredients, and worked recipe-scaling examples.