The mean of five numbers is 24. If four of the numbers are 18, 22, 26, and 30, what is the fifth number? - RTA

The mean of five numbers is 24. If four of the numbers are 18, 22, 26, and 30, what is the fifth number?
A question tapping into a familiar pattern of reasoning, this number puzzle continues to spark interest in math circles and casual learning communities across the U.S. With the mean serving as a foundational concept in statistics, understanding how to solve for unknown values helps build analytical confidence—especially when dealing with averages in real-life contexts like finance, gaming stats, or educational data.

Restating the problem: The mean of five numbers is 24, and four known values are 18, 22, 26, and 30. What is the missing fifth number? The mean, or average, is calculated by adding all numbers and dividing by how many there are. Since the overall average is 24 across five numbers, their total sum must be 24 multiplied by 5, which equals 120. Adding the known numbers—18 + 22 + 26 + 30—gives a sum of 96. Subtracting this from 120 reveals the missing number: 120 – 96 = 24. The fifth number is 24.

Why this question resonates now
The mean plays a quiet but steady role in digital literacy and data fluency trends in the U.S. As more people engage with data-driven apps, financial tools, and personalized planning platforms, understanding averages helps sort reliable insights from noise. Activity involving consistent data input—like tracking monthly expenses, sports performance, or goal progress—has grown in popularity, and simply calculating averages remains essential for interpreting results. Platforms and search interest related to average calculations continue rising, particularly in educational content and interactive math exercises popular on mobile devices.