Create a class bar graph representing the type of pets the students have at home. Ask the students to tell you the type of pet they have, or even if they do not own a pet. Count the number of students who have each pet (dog, cat, fish, etc.) and display this in the form of a graph. You can draw the graph on the chalkboard or create it on a large sheet of butcher paper. The age of the children can determine the complexity of the lesson. For younger children, simply learning what a bar graph is may be sufficient. For older children, you can teach them about the parts of a graph such as the title and labels for each axis.
Pets require food and water on a daily basis in order to live. Take a paper plate and have the students pretend that it represents their pet's food dish. Ask them to draw half a dish of food on the first plate. Then ask them to draw 1/4 a dish of food on the next plate. Continue this with as many fractions as you wish to use.
Students enjoy having a pet to care for in the classroom. A fish tank is relatively easy to manage and maintain. Surprise the students with an aquarium that you purchase at a pet store. Place a set number of fish in the tank. When you present the students with the new class pets, ask them to estimate the number of fish in the tank. Explain that estimation means guessing the number of something, and use the fish to demonstrate this concept. Record their estimates and then reveal the actual number of fish you placed in the tank.
To extend the pet math beyond the classroom, develop math worksheets that students can complete at home. Instead of using numbers to display the addition problem, use graphics of pets such as cats or dog in place of the numbers. For example, you might use two cat pictures, then write a plus sign, and use two dog pictures. Not only does this relate to the pet theme, it also helps children solve the problems through graphical representations of the numbers.