How to Find the Mean (Average)

Grades 6-7Key Stage 3Årskurs 6-7

Problem

Find the mean of: 12, 15, 18, 21, 24

📝Step-by-Step Solution

Understand what mean is

The mean is the average. It's found by adding all values and dividing by how many values there are.

Mean = Sum of all values / Number of values

Add all the numbers

12 + 15 + 18 + 21 + 24 = 90

Sum = 90

Count the numbers

There are 5 numbers in the data set.

Count = 5

Divide sum by count

Mean = 90 ÷ 5 = 18

✅Final Answer

Mean = 18

The mean represents the "center" of the data if all values were equal. Notice that 18 is literally the middle number here! The mean is affected by outliers (extreme values), so sometimes median is more representative.

Ready to Practice Mean, Median, Mode?

Generate a personalized practice test with MathQuizily. Get instant PDF downloads with answer keys.

Create Ready-to-Use Math Test (PDF)Ready in minutes. No editing needed.Open the AI math test generator

Learn more about Mean, Median, Mode

This worked example is part of the broader mean, median, mode guide. Review the method, practice related skills, and create a printable assessment when you are ready.

Open the Mean, Median, Mode guide

Back to Mean, Median, Mode Guide

Build the assessment, not just the questions

MathQuizily helps teachers move from a topic or standard to a printable math test with answer keys, balanced difficulty, and classroom-ready PDF output.

A useful assessment should make the learning target clear, cover the intended skills, and give the teacher enough information to review the result before students see it. The workflow supports short quizzes, chapter checks, diagnostic tests, homework packets, make-up assessments, and equivalent retake versions.

Choose a grade, topic, curriculum context, and difficulty level. The generated PDF includes a student version and a separate worked answer key, so teachers can print, review, and grade without reformatting questions or building solutions from scratch. No student account is required to create or print a test.