Math Guides: Percentages, Fractions and Statistics
The everyday math people look up most, explained step by step with numbers you can follow.
3 guides
Math
How to Calculate a Percentage (Percent of a Number, Percent Change, Reverse Percent)
How to calculate a percentage: divide the part by the whole and multiply by 100. Includes percent of a number, percent increase and decrease, and worked examples.
Updated Oct 27, 2026 · 4 min readMathHow to Convert a Decimal to a Fraction (Terminating and Repeating, With Chart)
How to convert a decimal to a fraction: write the digits over the place value of the last digit, then simplify. Covers mixed numbers, repeating decimals and a chart.
Updated Oct 27, 2026 · 4 min readMathHow to Find Standard Deviation (Sample and Population, Step by Step)
How to find standard deviation: subtract the mean from each value, square, add, divide by n (population) or n − 1 (sample), then take the square root.
Updated Oct 24, 2026 · 5 min read