Place number cards labeled one to 10 and a jar of shells in your classroom's math center. Instruct students to lay out the cards in numerical order and then place the correct number of shells on each card. Students may work together to finish this task.
Tie a string onto a wooden spoon or dowel rod. Attach a magnet at the end of a string. Cut out several fish from construction paper and have them laminated for extra durability. Make sure there are several fish of each color. Put a paper clip on each one. Students may go fishing to catch all the fish and then sort them according to color. Another variation is to write numbers on each fish and have the student say the number of the fish he caught. Students can also be instructed to catch a certain number of fish or all the fish of a certain color.
In the holes of a muffin tin, tape the numbers one to 10. Have students place the correct number of goldfish crackers in each "fish bowl." Colored goldfish crackers can also be used in a sorting activity. Serve goldfish crackers at snack time and have students count them before eating. Give children estimation practice by putting a few goldfish crackers in a clear glass. To keep this activity preschool-friendly, use 10 or fewer goldfish. Place the glass where all students can see and ask them to give their guess on how many goldfish are in the glass. Once everyone has had a turn to estimate, count the goldfish together to find the answer.
Sea life can also be used to create a classroom graph. After discussing various sea animals, poll the students to find their favorites. Create a graph on a whiteboard or chalkboard listing the sea animals from the class discussion on the bottom and numbers on the side. Fill in the graph according to the number of students who like each animal. Use ocean animal template or plastic figures for counting and sorting practice. Students may count the legs on each sea animal or sort the animals by color, kind, shape or number of legs.