MATH: Doodle Difference

Time Required: Two 45-minute sessions
Skill Level: Beginner
Recommended Grades: K to 2nd

Students work in pairs to subtract the difference within 20. They will decipher a color-key in order to Doodle a Doodle-Dog, bones, and bowls using the appropriate colors. Following this, students will create their own subtraction stories using Doodle-Dog to act it out.

Note: Any links outside of are optional resources. We can’t ensure their upkeep or accuracy.

Lesson Plan



For each group: Have 5 3Doodlers, and fill each one with one of these 5 colors: white, light blue, dark blue, green and orange. Place paper cups filled with refills of each of the 5 colors on the same table where students will be working. This same setup should be prepared for each group of 5 students.

*Optional: you can use a piece of masking tape to label which pens have what colors in them.

Step 2

Whole Group: Review subtraction facts with sums within 20.

Step 3

Share the goal: Solve problems with differences within 20 using Doodle-Dog Worksheet and 3Doodler.

Step 4

Review strategies for solving subtraction problems, e.g., counting on, making ten, decomposing a number leading to a ten and creating equivalent but easier or known sums.

Step 5

Model how to 3Doodle the Doodle-Dog Worksheet by solving a few of the problems. Explain that the differences in the color-key indicate which color should be doodled in each segment of the Doodle-Dog, bones and food dishes.

A) Outline each segment with the appropriate color first.
B) Fill in each section with the appropriate color.
C) Fill Doodle-Dog’s head first, doodling in the eyes last.
D) After doodling, students may add extra doodles, i.e., wavy lines or spirals to their doodled parts.

Step 6

After the demonstration, instruct students to solve all of the Doodle-Dog subtraction problems working in small groups. Review students’ answers to make sure they are correct.

Step 7

Instruct students on how to use the color-key to decipher colors. Have students color in first using color pencils first in order to confirm that they know which color goes in each segment of their Doodle-Dog. Check their work

Step 8

Hand out 5-3Doodlers and cups filled with refills to each group with one of 5 colors loaded into each one. Circle to assist and assess. The responsibility of doodling the Doodle-Dog, bones and bowls should be divided among each group.

Wrap Up

Students will share their Doodle-Dogs, bones, and bowls with peers. Students will make up their own subtraction problems that they will act out for the class using their doodles as the actors like puppets. Popsicle sticks can be attached to each one.


The teacher will assess students’ understanding of strategies based on their input during whole and small group work, their solutions to subtraction problems, and the students’ writing and enacting of their own Doodle Difference stories.

Possible Extensions

Students will use the same doodles to write their own Doodle-Difference stories and act them out for the class.


Outline each area first before filling. It is easier to segment off larger fill sections, as done here with pencil and then doodle with 3Doodler.

Optional: A stand can be doodled for the Doodle-Dog or any Doodle-Pals from other 3Doodler lessons.

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  • acting - the art or practice of representing a character before an audience.

  • collaboration - to work jointly with others or together especially in an intellectual endeavor.

  • color - the quality of an object or substance with respect to light reflected by the object, usually determined visually by measurement of hue, saturation, and brightness of the reflected light; saturation or chroma; hue.

  • drawing - the art or technique of representing an object or outlining a figure, plan, or sketch by means of lines.

  • problem-solving - the process or act of finding a solution to a problem.

  • subtraction - the operation of deducting one number from another.

  • writing - any written or printed paper, as a document or deed.

Educational Standards

Common Core

Fluently add and subtract within 20 using mental strategies.2 By end of Grade 2, know from memory all sums of two one-digit numbers.

In This Lesson

Students will solve subtraction problems using mental strategies in order to determine the colors needed for doodling each section of the Doodle-Dog, bones, and bowls.

CS Teachers

Decompose (break down) a larger problem into smaller sub-problems with teacher guidance or independently.

In This Lesson

Students will break down the process of determining colors for Doodle-Dog, bones, and bowls. by solving subtraction problems and using the related color key.


Use technology to seek feedback that informs and improves their practice and to demonstrate their learning in a variety of ways.

In This Lesson

Students will use the 3Doodler to create a doodled model of that displays their understanding of subtraction skills and strategies.


Create original works or responsibly repurpose or remix digital resources into new creations.

In This Lesson

Students will use a 3Doodler to create a dimensional model of a Doodle-Dog, bones, and bowls. based on subtraction sums and color key.


Use collaborative technologies to work with others, including peers, experts or community members, to examine issues and problems from multiple viewpoints.

In This Lesson

Students will seek feedback from peers as they solve subtraction problems, assign colors and doodle with 3Doodler.

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