Reading Stem and Leaf Plot Exercises

1. A zookeeper published the following stem-and-leaf plot showing the number of lizards at each major zoo in the country:
   
   $\begin{array}{|l|llllll}0 & & & & & & \\1 & & & & & & \\2 & 0 & 6 & 8 & 8 & 8 & \\3 & 0 & 2 & 6 & 6 & 7 & 8 \\4 & 1 & 2 & 6 & 6 & & \\5 & & & & & & \\6 & & & & & &\end{array}$
   
   Key: 4 |1=414 lizards
   
   What was the smallest number of lizards at any one zoo?
   
   
2. A zookeeper created the following stem-and-leaf plot showing the number of sloths at each major zoo in the country:
   
    $\begin{array}{|l|llll} 0 & 3 & & & \\ 1 & 6 & 7 & 7 \\ 2 & 0 & 4 & & & & \\ 3 & 0 & 1 & 1 & 2 & 4 & 7 & 9 & 9 \\ 4 & 1 & 2 & 3 & 5 & 7 \end{array}$
   
   Key: 4 |1=41 lizards
   
   How many zoos have exactly 17 sloths?
   
   
3. A statistician for a chain of department stores created the following stem-and-leaf plot showing the number of pairs of glasses at each of the stores:
   
    $\begin{array}{|l|llll} 0 & 9 & & & \\ 1 & 3 & 6 & 6 & 8\\ 2 & 1 & 2 & 3 & 5 & 6 & 9 \\ 3 & 0 & & & & && \\ 4 & 1 & 2 & 3 & 3 & 5& 7 \end{array}$
   
   Key: 4 | 1=41 pairs of glasses
   
   How many department stores have fewer than 38 pairs of glasses?
   
   
4. The government published the following stem-and-leaf plot showing the number of bears at each major zoo in the country:
   
   $\begin{array}{|l|lllll} 0 & & & & & & \\ 1 & 8 & 8 & & \\ 2 & 1 & 3 & 6 &6 &7&7&9 \\ 3 & 1& 7 & & & \\ 4 & 1 & 4 & 5 & 7 & & \\ 5 & 0 & 3 & & \end{array}$
   
   Key: 4 |1=414 bears
   
   How many zoos have more than 50 bears?
   

Source: Khan Academy, https://www.khanacademy.org/math/ap-statistics/quantitative-data-ap/histograms-stem-leaf/e/reading_stem_and_leaf_plots
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

1. The left column of the stem and leaf plot represents the tens place; each number on the right side represents the ones place for the number of lizards at a zoo.
   We can combine the tens and ones places and write out the number of lizards at each zoo on the right:
   
   $\begin{array}{|l|llllllllllllll}0 & & & & & & & \rightarrow & & & & & & \\1 & & & & & & & \rightarrow & & & & & & \\2 & 0 & 6 & 8 & 8 & 8 & & \rightarrow & 20 & 26 & 28 & 28 & 28 & \\3 & 0 & 2 & 6 & 6 & 7 & 8 & \rightarrow & 30 & 32 & 36 & 36 & 37 & 38 \\4 & 1 & 2 & 6 & 6 & & & \rightarrow & 41 & 42 & 46 & 46 & & \\5 & & & & & & & \rightarrow & & & & & & \\6 & & & & & & & \rightarrow & & & & & &\end{array}$
   
   Now we know the number of lizards at the different zoos:
   $20, 26, 28, 28, 28, 30, 32, 36, 36, 37, 38, 41, 42, 46, \text{and } 46$
   
    The zoo with the fewest lizards had 20 lizards.
   
   
2. The left column of the stem and leaf plot represents the tens place; each number on the right side represents the ones place for the number of sloths at a zoo.
   We can combine the tens and ones places and write out the number of sloths at each zoo on the right:
   
   $\begin{array}{|l|llll} 0 & 3 & & & & & & & & & \rightarrow & 03 & & & & \\ 1 & 6 & 7 & 7& & & & & && \rightarrow & 16 & 17 & 17 \\ 2 & 0 & 4 & & & && & & & \rightarrow & 20 & 24 & & \\ 3 & 0 & 1 & 1 & 2 & 4 & 7 & 9 & 9 & & \rightarrow & 30 & 31 & 31 & 32 &34&37& 39&39\\ 4 & 1 & 2 & 3 & 5 & 7& & & & & \rightarrow & 41 & 42 & 43&45&47 \end{array}$
   
   Now we know the number of sloths at the different zoos:
   $3, 16, 17, 17, 20, 24, 30, 31, 31, 32, 34, 37, 39, 39, 41, 42, 43, 45,  \text{and } 47$
   
   There are 2 zoos that match our question.
   
   
3. The left column of the stem and leaf plot represents the tens place; each number on the right side represents the ones place for the number of pairs of glasses at a department store.
   We can combine the tens and ones places and write out the number of pairs of glasses at each department store on the right:
   
   $\begin{array}{|l|llll} 0 & 9 & & & & & & \rightarrow & 09 \\ 1 & 3 & 6 & 6 & 8& & & \rightarrow & 13 & 16 & 16 & 18\\ 2 & 1 & 2 & 3 & 5 & 6 & 9 & \rightarrow & 21& 22& 23& 25& 26& 29 \\ 3 & 0 & & & & & & \rightarrow & 30 \\ 4 & 1 & 2 & 3 & 3 & 5& 7 & \rightarrow & 41 & 42 & 43 & 43 &45&47 \end{array}$
   
   Now we know the number of pairs of glasses at the different department stores:
   $9, 13, 16, 16, 18, 21, 22, 23, 25, 26, 29, 30, 41, 42, 43, 43, 45, \text{and }47$
   
   There are 12 department stores that match our question.
   
   
4. The left column of the stem and leaf plot represents the tens place; each number on the right side represents the ones place for the number of bears at a zoo.
   We can combine the tens and ones places and write out the number of bears at each zoo on the right:
   $\begin{array}{|l|lllllllllllllll}0 & & & & & & & & & \rightarrow & & & & & & \\1 & 8 & 8 & & & & & & \rightarrow & 18 & 18 & & & & & \\2 & 1 & 3 & 6 & 6 & 7 & 7 & 9 & \rightarrow & 21 & 23 & 26 & 26 & 27 & 27 & 29 \\3 & 1 & 7 & & & & & & \rightarrow & 31 & 37 & & & & & \\4 & 1 & 4 & 5 & 7 & & & & \rightarrow & 41 & 44 & 45 & 47 & & \\5 & 0 & 3 & & & & & & \rightarrow & 50 & 53 & & & &\end{array}$
   
   Now we know the number of bears at the different zoos:
   $18, 18, 21, 23, 26, 26, 27, 27, 29, 31, 37, 41, 44, 45, 47, 50, \text{and } 53$
   
   There is 1 zoo that matches our question.