Dr. Morrison, a pediatrician, weighed all the children who recently visited her office. How many children weighed exactly 41 pounds?
Stem | Leaf 
2 | 2, 5
3 | 4
4 | 1
5 | 0, 6
For the number 41, the stem is 4, and the leaf is 1. Find the row where the stem is 4. In that row, count all the leaves equal to 1.

You counted 1 leaf, which is blue in the stem-and-leaf plot above. 1 child weighed exactly 41 pounds.