Calculators— Guides & Articles

• How to Calculate the Absolute Value of a Complex Number

  Published 2026-07-27

  Find the modulus of a + bi: |z| = √(a² + b²). Step-by-step method, a worked example, and a free tool to verify each real-number step.

  

• 24 Game Solution: Find Exact Expressions for Any Hand

  Published 2026-07-27

  Need a 24 game solution for four whole numbers? Enter any four values 1–99 and get up to 50 exact expressions that equal 24, with parentheses shown.

  

• How to Calculate Back End BAC: Widmark Formula Guide

  Published 2026-07-27

  The back-end step of the Widmark BAC formula subtracts 0.015 percentage points per hour from a peak built on drinks, body weight, and sex. See inputs and…

  

• How to Read a Baby Eye Color Chart Before Baby Arrives

  Published 2026-07-27

  Read a baby eye color chart with our plain-English guide. Compare parents' eye colors, decode the percentages, and use a free calculator to predict brown,…

  

• How to Calculate Average in Excel: AVERAGE & More

  Published 2026-07-27

  Step-by-step guide to calculating average in Excel: AVERAGE, AVERAGEIF, AVERAGEIFS, MEDIAN, and MODE formulas plus a faster browser-based alternative.

  

• How to Find the Area of an Annulus: Formula and Steps

  Published 2026-07-26

  Find the area of any annulus with the free calculator. Enter R and r to get π(R² − r²), inner area, outer area, and ring width instantly — no math required.

  

• How to Convert Angle to Decimal Degrees

  Published 2026-07-26

  Convert any angle to decimal degrees — from radians, gradians, turns, DMS or arcminutes — using exact factors and a free browser-based Angle Converter.

  

• Age from DOB in Excel: Skip Formulas with a Calculator

  Published 2026-07-26

  Calculate age from a DOB in Excel using DATEDIF or YEARFRAC, then see how an instant Age Calculator does the same arithmetic without formulas.

  

• How to Calculate Absolute Value Step by Step

  Published 2026-07-26

  Learn the absolute value rule for any number — negatives, decimals, and scientific notation — with a free calculator that returns |x| live.

  

• 24 Game Answers: How to Make 24 from Any Four Numbers

  Published 2026-07-26

  Find exact 24 Game answers from any four whole numbers. Enter 1–99 in each field and get up to 50 verified expressions that equal 24.