How to Calculate What Percentage One Number Is of Another

Math with Mr. J

In this instructional mathematics video, "Mr. J" provides a clear, step-by-step demonstration of how to calculate what percentage one number is of another. Using the specific example problem "17 is what percent of 20?", the video breaks down the solution into a manageable three-step process: setting up a fraction, converting that fraction to a decimal through division, and finally converting the decimal to a percentage. Mr. J uses a digital chalkboard interface to write out calculations in real-time, making the mathematical procedure easy to follow visually. The video explores key mathematical themes including the relationship between fractions, decimals, and percentages, emphasizing that they are different representations of the same value. A significant portion of the video is dedicated to the mechanics of long division, specifically dividing a smaller number by a larger one to result in a decimal quotient. The instructor also introduces the "part over whole" concept, using a relatable analogy of a quiz score to help students conceptually understand why the fraction is set up with 17 as the numerator and 20 as the denominator. For educators, this video serves as an excellent resource for scaffolding lessons on rational numbers and percents. It is particularly useful for students who struggle with the algorithm for converting fractions to decimals or who need a refresher on long division with decimals. Teachers can use this video to model proper problem-solving procedures, illustrating how to set up word problems algebraically and how to check work. The practical "quiz score" analogy provides a natural entry point for classroom discussions about how grades are calculated, making the abstract math immediately relevant to student life.