Complete addition and subtraction sentences

Key notes :

🎇1.Understanding Addition and Subtraction Sentences

  • Addition Sentences: An equation that shows the sum of two or more numbers.
    • Example: 7+5=12
  • Subtraction Sentences: An equation that shows the difference between two numbers.
    • Example: 15−8=7

🎇2. Recognizing Missing Elements

  • Identifying the Missing Part: Understand whether the missing part is a number (addend, minuend, subtrahend) or the result (sum, difference).
    • Example: __+9=14 (Missing addend)
    • Example: 18−__=9(Missing subtrahend)

🎋3. Solving for Missing Numbers

  • Addition Sentences:
    • To find the missing addend: Subtract the known addend from the sum.
      • Example: __+9=14 → 14−9=5
    • To find the sum: Add the known addends.
      • Example: 7+8=__→ 7+8=15
  • Subtraction Sentences:
    • To find the missing minuend: Add the difference to the subtrahend.
      • Example: __−6=4 → 4+6=10
    • To find the missing subtrahend: Subtract the difference from the minuend.
      • Example: 12−__=5 → 12−5=7
    • To find the difference: Subtract the subtrahend from the minuend.
      • Example: 18−9=__→ 18−9=9

🎇. Checking Your Work

  • Verification: After solving, substitute the number back into the equation to ensure it makes the sentence true.
    • Example: For __+9=14, after finding 5 as the missing number, check that 5+9=14.

🎍5. Understanding the Relationship Between Addition and Subtraction

  • Inverse Operations: Recognize that addition and subtraction are inverse operations, which means they can be used to check each other.
    • Example: If 8+7=15, then 15−7=8

🧨6. Word Problems to Practice

  • Example 1: “Sarah has 23 apples. She buys some more apples, and now she has 37. How many apples did she buy?”
    • Solution: 23+__=37, so she bought 37−23=14 apples.
  • Example 2: “John had some money. After spending $35, he has $65 left. How much money did he have initially?”
    • Solution: __−35=65 so he initially had 65+35=100 dollars.

🧨7. Problem-Solving Strategies

  • Use a Number Line: Visualize addition or subtraction by moving forward or backward on a number line.
  • Estimate: Before solving, estimate the answer to see if your final answer is reasonable.
  • Draw a Picture: Sometimes drawing a simple diagram or using counters can help visualize the problem.

🎉8. Word Problem Connections

  • Application in Word Problems: Use addition and subtraction sentences to solve real-life problems, enhancing understanding and relevance.
    • Example: “If you score 23 points in the first half of a game and score 18 points in the second half, how many points did you score in total?”
      • Solution: 23+18=__so the total score is 41 points.

Learn with an example

Fill in the missing number.

68,094 – __________ = 60,755

  • Find the number that makes the subtraction number sentence true.
  • 68,094–?=60,755
  • Subtract 60,755 from both sides:
  • 68,094–? – 60,755=60,755 – 60,755
  • 7,339–?=0
  • Now, find the number that goes in the blank space. Remember, when a number is subtracted from itself, the difference is zero. The number in the blank space must be 7,339.
  • The missing number is 7,339.

Fill in the missing number.

________+ 48,995 = 89,668

  • Decide which number makes the addition number sentence true. You can subtract to find the answer.
  • Subtract: 89,668 – 48,995 = 40,673
  • The missing number is 40,673.

🗼 Fill in the missing number.

  • Find the number that makes the subtraction number sentence true.
  • 3,009 – ? = 2,915
  • Subtract 2,915 from both sides:
  • 3,009 – ? – 2,915 = 2,915 – 2,915
  • 94 – ? = 0
  • Now, find the number that goes in the blank space. Remember, when a number is subtracted from itself, the difference is zero. The number in the blank space must be 94.
  • The missing number is 94.

Let’s practice!