Kindergarten Math Study and Practice - Subtraction up to 10

Complete the Subtraction Sentence Up to 10

In some subtraction problems, one of the numbers is missing. Students figure out the missing number by thinking about what is taken away, what is left, and what was there to begin with. This helps build a clear understanding of subtraction as taking away or finding the difference between numbers.

Example Problems:

[] − 4 = 5 → Think: what number minus 4 equals 5? Answer: 9
8 − [] = 6 → Think: what number must be taken away from 8 to get 6? Answer: 2
7 − 3 = [] → Start at 7 and count back 3. Answer: 4

Teacher Tip

Encourage students to read each subtraction sentence out loud using “minus” and “equals” to strengthen both math vocabulary and comprehension.

Using Counters or Objects

Using real or visual objects, such as counters, blocks, or toy fruits, helps students test different possibilities until they find the missing number. This hands-on method turns subtraction into a concrete, visual activity.

Hands-On Examples:

[] − 2 = 6 → Try 8 counters: 8 − 2 = 6, so the missing number is 8.
5 − [] = 1 → Removing 4 counters leaves 1. The missing number is 4.
10 − 0 = [] → Removing nothing leaves all 10. The missing number is 10.

Helpful Strategy

Have children physically remove counters and count what is left. This reinforces the idea that subtraction means “taking away.”

Counting Back and Counting Forward

When the first number is known, counting back on a number line or with fingers helps find the answer. If the first number is missing, students can count forward from the result to see how many steps it takes to reach the starting number.

Counting Strategies:

9 − [] = 4 → Count forward from 4 to 9: 5, 6, 7, 8, 9. That’s 5 steps, so the missing number is 5.
[] − 3 = 7 → Start at 7 and count forward 3 steps to get 10. Missing number is 10.
6 − 2 = [] → Count back from 6: 5 → 4. Answer is 4.

Instructional Tip

Model both counting back and counting forward on a large classroom number line so students can visually connect the steps.

Writing Subtraction Sentences in Different Forms

Writing subtraction sentences helps students represent problems clearly and check their work. They learn that the missing number can appear in the first position, second position, or as the answer, and they can still find the solution.

Subtraction Sentences:

[] − 5 = 2 → Missing number is 7.
4 − [] = 0 → Missing number is 4.
8 − 6 = [] → Missing number is 2.

Math Language

Encourage children to re-read the subtraction sentence after solving to ensure it makes sense both mathematically and in words.

Checking the Solution

Students should check their answer by substituting the missing number back into the subtraction sentence to see if it makes a true statement. This confirms their thinking and builds accuracy.

Checking Examples:

[] − 3 = 5 → Try 8: 8 − 3 = 5 ✓
7 − [] = 2 → Try 5: 7 − 5 = 2 ✓
10 − 4 = [] → Try 6: 10 − 4 = 6 ✓

Helpful Tip

Teach students that checking is like proving their answer is correct, just as they would test a puzzle piece to make sure it fits.

Real-Life Connections

Relating subtraction to everyday activities helps children see its usefulness. Situations like eating snacks, sharing toys, or using crayons naturally involve taking away and finding what is left.

Real-Life Examples:

You have 7 apples and eat 2. How many are left? 7 − 2 = 5.
There are 10 cars, and 4 drive away. How many are still there? 10 − 4 = 6.
You start with 5 balloons, and 5 fly away. How many remain? 5 − 5 = 0.

Engagement Tip

Use classroom or home scenarios so students can connect subtraction to their own experiences, making the skill more memorable.

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