Adding and Subtracting on a Number Line

Adding and subtracting on a number line activity

Last month when we were at the beach, we saw a few dolphins swimming off in the ocean. One of us would spot them and exclaim, and then the rest of us would anxiously watch a little further to the right or left to see if we could catch of glimpse of them when they resurfaced. Watching these beautiful animals glide and slip above the water gave me a fun idea for adding and subtracting on a number line!

Dolphin Number Line Activity


  • blue and gray cardstock
  • printable number line template (0-10 or 0-20)
  • dolphin templates
  • popsicle stick
  • clear tape
  • stick glue
  • scissors


1. Print the number line on blue cardstock. Cut along the waves at the top. Cut along the dotted line above the number line making sure not to cut all the way to the edges.

2. Print two dolphins on gray cardstock and cut them out. (Optional: print on white cardstock and color them gray.) Tape the end of a popsicle stick to the back of one dolphin. Glue the other dolphin on top of this dolphin so there’s a dolphin on both sides of the popsicle stick.

Adding and subtracting on a number line activity

3. Insert the popsicle stick in the opening above the number line. To add, move the dolphin along the number line to the right. To subtract, flip the popsicle stick over and move the dolphin along the number line to the left.

Click on the link below to download the number line and dolphin templates to make your own! I included number lines to ten and twenty. The download does not include the flashcards. Use the dolphin number line with any math worksheets or flashcards you may have.

Click Here for the Free Download

This adding and subtracting on a number line activity is part of my Dolphin Activities for Kindergarten and First Grade.  It includes cross-curricular activities for science, reading, writing, math and art. The best part? It also includes a lesson plan and teaching guide for you!

More Ocean Resources

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Ocean Videos for Kids

Whale Art Project for Kids

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  1. This is wonderful ! I Love it and can’t wait to use it. My students are having a hard time using a number line and I know this will help.

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