Mental Strategies in Maths: Efficient methods for performing mathematical calculations in your head without using external tools or writing anything down
Addition: Combining numbers to find a total
Subtraction: Taking away to find the difference
Inverse Operations: Addition and subtraction are opposite operations
Number Sense: Understanding how numbers relate to each other
- Analyze the numbers: Look for patterns and relationships
- Choose the best method: Select the most efficient strategy
- Apply the technique: Follow the steps for chosen strategy
- Verify the answer: Check by adding or using another method
• Flexibility: Different problems may require different strategies
• Practice: Regular practice builds fluency and confidence
• Verification: Always check your answers
• Confidence: Start with easier problems and progress gradually
Counting Back: Starting from the minuend (first number) and counting backward by the number of steps equal to the subtrahend (second number)
- Start at the first number (minuend)
- Count backward one number at a time
- Count the same number of steps as the second number (subtrahend)
- The final number is your answer
Number Bonds: Understanding that addition and subtraction are inverse operations; knowing that if a + b = c, then c - a = b and c - b = a
- Identify the subtraction problem: minuend - subtrahend = ?
- Rewrite as an addition problem: subtrahend + ? = minuend
- Solve the addition problem using known facts
- The answer is the same for both problems
Compensation: Adjusting numbers to make calculation easier, then adjusting the answer accordingly
Answer: 3
Answer: 8
- Round the subtracted number up to the nearest ten
- Subtract the rounded number from the first number
- Add back the difference between the rounded number and the original
- The result is your answer
Doubles Facts: Using known doubles (like 6 + 6 = 12) to solve related subtraction problems
Answer: 5
Answer: 7
- Recognize if the subtraction involves a double
- Recall the corresponding addition fact
- Apply the inverse relationship
- The answer is the same as the double number
Decomposing: Breaking apart the number being subtracted into smaller, easier-to-manage parts
So: 13 - 3 - 3 = 10 - 3 = 7
Answer: 7
So: 15 - 5 - 3 = 10 - 3 = 7
Answer: 7
- Break the subtracted number into smaller parts
- Subtract each part one at a time
- Continue until you reach the final answer
- Combine the results
Mental Maths: Calculating in your head without external tools
Number Bonds: Pairs of numbers that add up to a given total
Compensation: Adjusting numbers to make calculations easier
Decomposing: Breaking numbers into smaller parts
Mathematical Fluency: Ability to perform calculations quickly and accurately
- Subtracting 1-3: Use counting back
- Subtracting 4-5: Counting back or number bonds
- Subtracting 6-7: Number bonds or decomposition
- Subtracting 8-9: Compensation (think 10 and adjust)
- Doubles: Use doubles facts (12-6, 16-8)
Commutative Property: a + b = b + a (applies to addition)
Associative Property: (a + b) + c = a + (b + c) (applies to addition)
Inverse Operations: Addition and subtraction are opposite operations
Identity Element: a + 0 = a, a - 0 = a
• Commutative Property: Does NOT apply to subtraction (a - b ≠ b - a)
• Associative Property: Does NOT apply to subtraction
• Identity Property: a - 0 = a
• Inverse Operations: Addition and subtraction undo each other
- Consistent Practice: 10-15 minutes daily
- Start Simple: Master basics before advancing
- Visualize: Use mental images or physical objects
- Check Answers: Verify by adding back
- Build Confidence: Celebrate small improvements
- Week 1-2: Focus on counting back strategy
- Week 3-4: Introduce number bonds
- Week 5-6: Practice compensation
- Week 7-8: Work on doubles facts
- Week 9-10: Combine all strategies
• Counting Errors: Miscounting steps when counting back
• Compensation Confusion: Forgetting to add back the difference
• Wrong Strategy: Using a complex method for simple problems
• No Verification: Not checking answers