A stem and leaf plot displays data by breaking each data point into two parts: the "stem" and the "leaf." Each stem represents a range of values (e.g. if the stem is 2, the corresponding leaves might be data points in the 20s). Each leaf typically represents the last digit of a data point (e.g. if the leaf is 6 next to a stem of 2, it could represent a data point whose value is 26). Created by Sal Khan.
The government created the following stem-and-leaf plot showing the number of turtles at each major zoo in the country. How many zoos have fewer than 46 turtles? So what the stem-and-leaf plot does is it gives us the first digit in each number and essentially you could call this the tens place. And then it gives us the ones place. So there was only one zoo that had four turtles. So you could view this as 0, 0, 4, or 4 turtles. Then everything here, the tens place, is a 1. So this number right here is really an 11. This is a 14. This right over here would be a 16. That's a 16, and so forth and so on. This would be 17, 18. All of this is 23. This is 23. This is 26 because we have our tens place right over here. This is the first digit. So let's answer the question. How many zoos have fewer than 46 turtles? So there are no zoos that had 40 anything turtles. And so all of these zoos here-- so all of these had 30 something turtles, these had 20 something turtles, these have in the teens, this has single digits. So it's literally as many zoos as we have listed here. So 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17. 17 zoos have fewer than 46 turtles. Let's do another one. The buyer for a chain of supermarkets created the following stem-and-leaf plot showing the number of coconuts at each of the stores. What was the smallest number of coconuts at any one grocery store? So the buyer for a chain of supermarkets created the following stem-and-leaf plot showing the number of coconuts at each of the stores. So at any one grocery store the smallest number-- well, that's this one right over here. And remember, it's not two. We have our tens places right over here. It's a one. So this right over here represents 12 coconuts at that store. So we'll put 12 right over here. Let's try another one. A statistician for a chain of department stores created the following stem-and-leaf plot showing the number of watches at each of the stores. How many department stores have exactly seven watches? Well that's only this one right over here-- 07 watches. This one, this, this, and that one are not 7. This is representing 17 because it's in the row with 1 at the beginning. This right over here represents 27 because it's in the row with the 2 at the beginning. So there's only one store that has exactly seven watches. Let's do one more. This is kind of fun. A zookeeper created the following stem-and-leaf plot showing the number of tigers at each major zoo in the country. How many zoos have more than 24 tigers? So we can ignore the zeros and the teens and we get in the 20s. This is 25. So that meets the criteria. And then you go to 28, 29. So all of these in the 30s and all of these right over here. This 3, 0-- this doesn't mean 0 tigers. This is 30 tigers. This is 40 tigers. So we count 1, 2, 3, 4, 5, 6, 7, 8, 9, 9 zoos have more than 24 tigers. 9 zoos. And we're done.