Mental Math Strategies

Grade 2 · mathematics · 92 practice problems · read aloud

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🧠 Mental Math Strategies

What is Mental Math?

Mental math is solving problems in your head without using paper, a calculator, or counting on your fingers! It's useful because it makes you a faster and more confident math thinker. 🚀

How to Solve Problems Mentally

  1. Look for Friendly Numbers: Find numbers that are easy to work with, like 10 or 5.
  2. Break Numbers Apart: Split a number into tens and ones to make adding easier.
  3. Put It Back Together: Add the parts you made to find the final answer.

Visual Examples

Example 1: 24 + 12

1. Break 24 into 20 + 4.
2. Break 12 into 10 + 2.
3. Add the tens: 20 + 10 = 30.
4. Add the ones: 4 + 2 = 6.
5. Put it together: 30 + 6 = 36. ✅

Example 2: 36 + 25

1. Make a friendly number: 36 needs 4 to make 40.
2. Take 4 from 25, so 25 = 4 + 21.
3. Add 36 + 4 = 40.
4. Now add the rest: 40 + 21 = 61. ✅

Common Mistakes to Avoid

⚠️ Forgetting to Regroup: When you break a number apart, remember all its parts! If you have 15, it's 10 and 5, not 1 and 5.

⚠️ Mixing Tens and Ones: Always add tens to tens and ones to ones. 20 + 5 is 25, not 205!

Tips & Tricks

Doubles are your friend! Remembering doubles like 6+6=12 can help you solve nearby problems like 6+7.

Use "Make a Ten": Always look for ways to make 10. For 8 + 5, think: 8 + 2 = 10, then 10 + 3 = 13.

Count On: For adding 1, 2, or 3, just count up from the bigger number.

How to Practice

  • Flashcards: Practice doubles (5+5, 6+6) and facts that make 10 (7+3, 4+6).
  • Math Games: Play "I Spy" with math problems. "I spy something and 5+7 tells you how many!"
  • Everyday Math: At the store, ask "If this costs 4 dollars and this costs 3 dollars, how much is that altogether?"

Practice problems

6 of the 92, worked through step by step — try them before opening the answer.

1 47 + 25 = ?

Hint: Think about adding the tens first, then the ones, and combining them together

Show the answer

Answer: 72

  1. Break 47 into 40 + 7 and 25 into 20 + 5
  2. Add the tens: 40 + 20 = 60
  3. Add the ones: 7 + 5 = 12
  4. Combine the results: 60 + 12 = 72

The answer is 72.

2 47 + 26 = ?

Hint: Try breaking one number into parts to make adding easier

Show the answer

Answer: 73

  1. Start with 47 + 26
  2. Break 26 into 20 + 3 + 3 to make adding easier
  3. Add 47 + 20 = 67
  4. Add 67 + 3 = 70
  5. Add 70 + 3 = 73

The answer is 73.

3 63 + 29 = ?

Hint: Think about adding the tens and ones separately, then combining them.

Show the answer

Answer: 92

  1. Break 63 into 60 + 3 and 29 into 20 + 9.
  2. Add the tens: 60 + 20 = 80.
  3. Add the ones: 3 + 9 = 12.
  4. Combine the results: 80 + 12 = 92.

The answer is 92.

4 58 + 36 = ?

Hint: Try breaking one number into parts to make a friendly number first

Show the answer

Answer: 94

  1. Start with 58 + 36
  2. Break 36 into 2 + 34 to make adding easier
  3. Add 58 + 2 = 60
  4. Add 60 + 34 = 94

The answer is 94.

5 68 + 27 = ?

Hint: Try breaking one number into parts to make a friendly number first

Show the answer

Answer: 95

  1. Start with 68 + 27
  2. Break 27 into 2 + 25 to make adding easier
  3. Add 68 + 2 = 70
  4. Add 70 + 25 = 95

The answer is 95.

6 48 + 35 = ?

Hint: Try breaking one number into parts to make a friendly number first

Show the answer

Answer: 83

  1. Start with 48 + 35
  2. Break 35 into 2 + 33 to make adding easier
  3. Add 48 + 2 = 50
  4. Add 50 + 33 = 83

The answer is 83.

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