Kindergarten Math - Study and Practice: Addition and Subtraction Up to 10

Completing Addition and Subtraction Sentences Up to 10

Some number sentences have a missing number. Students solve by deciding what is added or taken away, what remains, and what was there to begin with. This builds strong understanding of how numbers work together in different positions within an equation.

Example Problems:

[] + 4 = 7 → What number plus 4 equals 7? Answer: 3
9 − [] = 6 → How many must be taken away from 9 to get 6? Answer: 3
2 + 5 = [] → Start at 2 and count up 5. Answer: 7

Teacher Tip

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

Using Objects or Visual Models

Using real or visual objects, such as counters, blocks, or pictures, helps students try out different possibilities until they find the missing number. This hands-on method makes math ideas more concrete and easier to understand.

Hands-On Examples:

[] − 2 = 5 → Try 7 counters: 7 − 2 = 5, so the missing number is 7.
6 + [] = 10 → Add 4 counters to 6 counters: total is 10, so the missing number is 4.
8 − 0 = [] → Taking away nothing leaves 8, so the missing number is 8.

Helpful Strategy

Have students physically add or remove counters, then count the total. This reinforces that addition means “putting together” and subtraction means “taking away.”

Counting Strategies

When the first number is known, counting forward helps solve addition problems, and counting backward helps solve subtraction problems. If the first number is missing, students can count up from the result to the total for addition, or from the result to the starting number for subtraction.

Counting Examples:

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

Instructional Tip

Model counting forward and backward using a number line or fingers. This gives students a clear, visual way to keep track of their counting steps.

Writing Number Sentences in Different Forms

The missing number can be in any position in a number sentence: the first number, the second number, or the answer. Recognizing this flexibility helps students become confident problem solvers.

Examples:

[] + 7 = 10 → Missing number is 3.
5 − [] = 2 → Missing number is 3.
4 + 4 = [] → Missing number is 8.

Math Language

Have students restate the problem in words after solving, such as “Three plus seven equals ten,” to connect spoken and written forms of math.

Checking the Answer

Students should check their answer by putting the missing number back into the sentence to see if it is correct. This habit improves accuracy and teaches self-correction.

Checking Examples:

[] + 6 = 9 → Try 3: 3 + 6 = 9 ✓
10 − [] = 8 → Try 2: 10 − 2 = 8 ✓
7 + 2 = [] → Try 9: 7 + 2 = 9 ✓

Helpful Tip

Remind students that checking is like fitting the last piece into a puzzle — it should fit perfectly without forcing.

Connecting to Real-Life Situations

Linking math problems to everyday activities makes learning meaningful. Examples like sharing snacks, putting away toys, or counting steps can turn into simple math sentences to solve.

Real-Life Examples:

You have 4 apples and get 5 more. How many in all? 4 + 5 = 9.
You have 8 crayons and give away 3. How many left? 8 − 3 = 5.
You see 10 ducks, and 7 fly away. How many remain? 10 − 7 = 3.

Engagement Tip

Use relatable situations to help students picture and connect with the math they are learning, making it easier to remember and apply.

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