
Do you use fun strategies to teach students to subtract within 20? Subtraction is an essential skill in early math, and when students develop a strong foundation, they gain confidence in problem-solving. One of the important parts to help students understand subtraction is by focusing on three simple subtraction rules which are subtracting zero, subtracting one, and subtracting the same number. Let’s look at engaging ways to practice these concepts using manipulatives, drawings, and writing out equations!
Are you looking for an engaging way to practice how to subtract within 20 in your classroom? This Roll and Write Activity is a great way to build subtraction skills. You can use it for a math center, in a small group, or as a math activity for fast finishers. Students need a dice, a paper, and a pencil. Then they are on their way to building their math fact fluency skills. Put your name and email in the boxes, and it will quickly be in your inbox to use in your classroom!
Subtracting Zero from a Number
When you subtract zero from a number, the number stays the same. This is a simple fact for students to master. It builds confidence and helps them see patterns in math. Here are some fun ways to practice subtracting zero.

Use Manipulatives to Subtract within 20
Give students a handful of counters, cubes, or small objects. Ask them to count out a number, like 7, and then subtract zero. I like to play with them and make a big deal about asking them why they still have 7 counters on their table. They love it and quickly see that the number remains the same. You can also have them record their findings in a math journal to reinforce the concept.
Draw It Out
Have students draw pictures to represent numbers. For example, they can draw 5 circles and then cross out zero. Ask, “How many are left?” This visual method helps students understand that subtracting zero does not change the total.
Write the Equations
Encourage students to write out subtraction sentences such as:
- 6 – 0 = 6
- 9 – 0 = 9
- 15 – 0 = 15
By writing equations, students will see the pattern that subtracting zero leaves the number unchanged.
Subtract Within 20: Subtracting One
Subtracting one is a crucial skill that helps students with number sequencing and prepares them for subtraction within 20.

Use Manipulatives
Give students a set number of objects such as 8 cubes. Have them physically remove one cube and count how many are left. Repeat this with different numbers to help them see the pattern that subtracting one gives the previous number.
Draw It Out
Students can draw a set of squares and cross one out. For example, if they draw 7 squares and erase one, they can count how many remain. This strategy helps reinforce one less than a given number.
Write the Equations
Writing equations helps students recognize the pattern:
- 8 – 1 = 7
- 12 – 1 = 11
- 20 – 1 = 19
I also like to discuss how subtracting one is like counting backwards. This helps to strengthen their number sense.
Subtract within 20: Subtracting the Same Number
When a number is subtracted from itself, the result is always zero. This is an important math fact that helps students understand subtraction and develop fact fluency.

Use Manipulatives
Ask students to count out a set number of objects such as 4 cubes and then remove all of them. Once again, I like to play with them and see why they don’t have anything left. This reinforces that any number minus itself equals zero.
Draw It Out
Have students draw a group of objects, such as 4 apples, and then cross out all of them. Ask, “How many are left?” This visual approach reinforces the idea that subtracting all of something results in zero.
Write the Equations
Practicing these equations will help students recognize the pattern:
- 3 – 3 = 0
- 7 – 7 = 0
- 10 – 10 = 0
Encourage students to create their own subtraction sentences to further practice this concept. They like making really large equations such as 100-100=0.
Making Subtract Within 20 Fun
Subtraction practice doesn’t have to be repetitive or boring. Here are a few engaging ways to reinforce these subtraction rules.

Games and Activities
- Spin and Play: Use these games to practice focused subtraction facts along with pages of mixed facts. Students spin, write the subtraction equation in the box, and solve it. You can focus on specific facts to practice math facts.
- Roll and Write: Roll a die, look at the same number on the page, and solve the equation. There are pages to help you focus on specific facts such as subtracting 0 and 1 along with pages with mixed facts.
- Color by Code: Have students solve subtraction equations to reveal a hidden picture.
Real-Life Connections to Subtract within 20
- Snack Time Subtraction: Give students a small snack and have them eat one at a time while stating the subtraction equation. They love this activity!
- Classroom Subtraction: Ask questions such as “We had 10 markers, and we lost one. How many do we have now?”
By using manipulatives, drawings, and written equations, students will develop a deep understanding of subtraction within 20 while having fun. Try these strategies in your classroom and watch your students build confidence in their math skills!
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