In our 'street' there a lot of people, mostly with ages different from the others in the street. But there are some who have the same age. The mode is that value which appears most often - the 'commonest' value. The mode is useful when we want to understand any pattern (or distribution) in the data. If the mode is very near to or similar in value to the mean this might suggest distribution which is 'normal', whereas if the mode was very different from the mean then this might suggest a very different distribution (which may be described as 'skewed'). In a normal distribution the mean, mode and median are the same value. Imagine that the average age for our street is 35 years, and our mode is 34 years. These values are very close to each other. Such a combination might suggest a near normal distribution. Now imagine that the average is still 35 years, but that the mode is 20 years. That is, we now have a lot of people who share the same age who are very different from the average. This might suggest a skewed distribution.