Solved Exercises on Mental Math Strategies for Grade 1

Master mental math strategies: addition and subtraction with visual infographics, step-by-step solutions, and practice problems.

Mental Math Strategies Concepts & Visuals
MENTAL MATH STRATEGIES SUMMARY

Definition: Mental math strategies are techniques that allow students to solve math problems in their head without writing anything down.

Core Rules:

  • Use number relationships and patterns
  • Break problems into easier parts
  • Use known facts to solve unknown problems
  • Choose the most efficient strategy for each problem

Methods: Counting on, making tens, using doubles, breaking apart numbers, and other efficient techniques.

Examples: 5 + 3 = 8 (think: start at 5, count 3 more), 7 + 6 = 13 (think: 7 + 3 = 10, then 10 + 3 = 13)

Tips: Practice regularly, use visual aids, and connect to real-life situations.

🧠 Mental Math Strategies
Solve math problems in your head using efficient techniques
Definition:

Mental Math Strategies: Techniques for solving math problems using only your mind, without writing or counting on fingers.

Mental Math Methods:
  1. Counting On: Start with the larger number and count up
  2. Make a Ten: Break numbers to create 10
  3. Use Doubles: Apply known doubles facts
  4. Break Apart: Separate numbers into easier parts
Counting On
5 + 2 → 5, 6, 7
Making Ten
8 + 5 → 8 + 2 + 3 = 13
Using Doubles
6 + 7 → 6 + 6 + 1 = 13
Breaking Apart
9 + 4 → 9 + 1 + 3 = 13
Key Rules:

• Think Before Calculating: Choose the most efficient strategy

• Use Known Facts: Apply memorized number relationships

• Work Left to Right: Start with the most significant numbers

• Check Your Work: Verify mentally when possible

Tip 1: Practice simple facts until they become automatic.
Tip 2: Use visualization to "see" the numbers in your mind.
Tip 3: Start with small numbers and gradually increase difficulty.
Solution: Exercises 1 to 3
1 Counting On Strategy
Exercise 1
Solve 6 + 3 mentally
Strategy:

Counting On: Start with the larger number and count up.

Thinking Process: Start at 6, count 3 more: 7, 8, 9
Step 1: Identify the larger number

Start with 6 (the larger number)

Step 2: Count up by the smaller number

Count 3 more: 7, 8, 9

Step 3: State the answer

6 + 3 = 9

6 + 3 = 9
Final answer:

6 + 3 = 9

Applied rules:

• Start with Larger: Begin with the larger addend

• Sequential Counting: Count up one number at a time

• Mental Tracking: Keep track of counts in your head

2 Making Ten Strategy
Exercise 2
Solve 8 + 5 mentally
Strategy:

Making Ten: Break apart 5 to make 10 with 8.

Thinking Process: 8 needs 2 more to make 10, so break 5 into 2 and 3. Then 10 + 3 = 13
Step 1: Identify what's needed to make 10

8 needs 2 more to make 10

Step 2: Break apart the second number

Break 5 into 2 and 3

Step 3: Make 10

8 + 2 = 10

Step 4: Add the remaining part

10 + 3 = 13

8 + 5 = 13
Final answer:

8 + 5 = 13

Applied rules:

• Decomposition: Break numbers strategically to make 10

• Sequential Addition: Add in parts (make 10, then add remainder)

• Number Bonds: Know that 8 + 2 = 10

3 Using Doubles Strategy
Exercise 3
Solve 7 + 6 mentally
Strategy:

Using Doubles: Use known doubles fact and adjust.

Thinking Process: I know 6 + 6 = 12, and 7 is 1 more than 6, so 7 + 6 = 12 + 1 = 13
Step 1: Recognize the near doubles pattern

7 + 6 are consecutive numbers (near doubles)

Step 2: Use the doubles fact

6 + 6 = 12 (known doubles fact)

Step 3: Adjust for the difference

7 is 1 more than 6, so add 1 to the doubles answer

Step 4: Calculate the final answer

6 + 6 + 1 = 12 + 1 = 13

7 + 6 = 13
Final answer:

7 + 6 = 13

Applied rules:

• Doubles Recognition: Identify near doubles patterns

• Known Facts: Use memorized doubles facts

• Incremental Adjustment: Add difference to doubles result

Solution: Exercises 4 to 5
4 Breaking Apart Strategy
Exercise 4
Solve 9 + 4 mentally
Strategy:

Breaking Apart: Break 4 to make 10 with 9.

Thinking Process: 9 needs 1 more to make 10, so break 4 into 1 and 3. Then 10 + 3 = 13
Step 1: Identify what's needed to make 10

9 needs 1 more to make 10

Step 2: Break apart the second number

Break 4 into 1 and 3

Step 3: Make 10

9 + 1 = 10

Step 4: Add the remaining part

10 + 3 = 13

9 + 4 = 13
Final answer:

9 + 4 = 13

Applied rules:

• Strategic Breaking: Break numbers to create 10

• Sequential Addition: Add in parts (make 10, then add remainder)

• Number Bonds: Know that 9 + 1 = 10

5 Mental Math Challenge
Exercise 5
Solve 5 + 7 mentally
Strategy:

Using Doubles: Use known doubles fact and adjust.

Thinking Process: I know 5 + 5 = 10, and 7 is 2 more than 5, so 5 + 7 = 10 + 2 = 12
Step 1: Recognize the near doubles pattern

5 + 7 can be thought of as 5 + 5 + 2

Step 2: Use the doubles fact

5 + 5 = 10 (known doubles fact)

Step 3: Add the remaining part

10 + 2 = 12

Step 4: Calculate the final answer

5 + 7 = 12

5 + 7 = 12
Final answer:

5 + 7 = 12

Applied rules:

• Doubles Recognition: Identify opportunities to use doubles

• Known Facts: Use memorized doubles facts

• Sequential Addition: Add parts together mentally

Questions & Answers

Question: Why do we need to do math in our heads? Isn't it easier to write it down?

Answer: Mental math is like having a superpower for everyday life! Here's why it's important:

Benefits of mental math:

  • It's faster for simple calculations
  • It builds number sense and confidence
  • It helps in real-life situations (shopping, cooking, etc.)
  • It strengthens your brain and memory

Writing things down is helpful for complex problems, but mental math helps you become a quick thinker!

Question: My child gets confused about which strategy to use. How can I help them choose?

Answer: Choosing the right strategy comes with practice! Here are some guidelines:

Strategy selection tips:

  • Numbers close to 10: Use "making ten" strategy (8 + 4, 9 + 3)
  • Consecutive numbers: Use doubles strategy (6 + 7, 8 + 9)
  • Small additions: Use counting on (5 + 2, 7 + 1)
  • Practice: Try different strategies and see which feels easiest

Encourage your child to experiment with different strategies and pick the one that feels most comfortable!

Question: What if I forget the answer in my head? How can I remember it?

Answer: It's normal to forget! Here are some memory aids:

Memory strategies:

  • Repeat the answer: Say it out loud a few times
  • Use a backup method: Write it down if you're stuck
  • Check with a friend: Ask yourself if the answer makes sense
  • Practice regularly: The more you practice, the more automatic it becomes

Remember, everyone starts by learning slowly - with practice, mental math becomes easier!