All About Leaves - How Many Are On The Tree? November 11 2009

I love to watch the leaves change color this time of year, but it never occurred to me to try and figure out how many leaves might be on a tree...until they all fall in my yard, and I have to rake them. Before that happens, consider completing this math activity with your students!

If you've already done All About Leaves: The Observation with your class, this math lesson will probably be easier to do. While you're collecting leaves for the Observation, use pruners to snip a branch (or two, or three, depending on what you decide to do) from three or four different kinds of trees. Make sure there are leaves on the branches, and it would probably be best to choose branches from trees around your school if possible.

What do your students do with the branches? The original idea is to use them to estimate and figure out how many leaves are on the tree, but I wanted to modify that idea to include a variety of skill and age levels. The following problems are arranged from easiest to hardest, and could be used for center times, individual work, or whole-group lessons.

Hard 

  • How many leaves are on the branch? Make 5 to 10 number sentences and write or draw them on a piece of paper or in a math journal (depending on what skills your class is working on, these could be addition, subtraction, multiplication or division).
  • There is an easy graphing idea to use with a leaf collection from my All About Leaves post,  Getting Started

Harder

  • Compare the amount of leaves on branches of different kinds of trees using the Branch Comparison Chart. Discuss similarities, differences, and patterns kids can see from their work with the branches. They can write their observations on the back of the chart.
  • Find the area of a leaf. Students choose a leaf and trace it onto graph paper, then count the number of squares the leaf covers. The area will be in square units, and will be an approximate measurement.

Hardest

  • Use the Branch Comparison Chart exercise above to find the average number of leaves on a branch. Using that information, how can your students figure out how many leaves are on each tree? Write their ideas on chart paper, and visit the trees if necessary to find the estimated number of branches on the trees from which the branches came (If they don't eventually come to this conclusion, consider suggesting that they multiply the average number of leaves per branch by the estimated number of branches).
  • Fine the area of a leaf using square centimeter graph paper. Students must calculate the exact measurement in square centimeters. Challenge them by asking How they can figure out the total area of the leaves on the tree? Is greater "leaf area" important? Why or why not? (It is, because greater leaf area = more photosynthesis).

A combination of these exercises may be a good balance, especially considering the spectrum of skill levels in one classroom. And don't forget that these can be used with small groups, individually, whole class or in centers!