Choose numbers with a particular sum

Key notes :

🎈1. Understanding the Concept

  • Particular Sum: The goal is to select numbers that add up to a given total.
  • Purpose: Helps students practice addition skills, understand number relationships, and enhance problem-solving abilities.

🎆2. Steps to Choose Numbers with a Particular Sum

  1. Identify the Total Sum:
    • Clearly understand the sum you need to achieve.
    • Example: The target sum is 50.
  2. List Possible Numbers:
    • Think of numbers that could potentially add up to the target sum.
    • Example: For a sum of 50, possible numbers could be 20, 30, 25, etc.
  3. Test Combinations:
    • Add different combinations of the numbers to see if they meet the target sum.
    • Example:
      • 20 + 30 = 50 (Correct combination)
      • 25 + 15 + 10 = 50 (Another correct combination)
  4. Check for Multiple Solutions:
    • There may be more than one combination that adds up to the target sum.
    • Example: For a sum of 40, combinations could include 10 + 30, 20 + 20, 15 + 25, etc.
  5. Verify the Solution:
    • After selecting numbers, double-check the addition to ensure it equals the target sum.
    • Example: Verify 20 + 30 = 50 by adding the numbers again.

🧨3. Example Problems

  1. Example 1:
    • Problem: Choose numbers that add up to 60.
    • Solution:
      • Combination 1: 20 + 40 = 60
      • Combination 2: 10 + 25 + 25 = 60
      • Combination 3: 30 + 30 = 60
  2. Example 2:
    • Problem: Find numbers that sum to 45.
    • Solution:
      • Combination 1: 15 + 30 = 45
      • Combination 2: 20 + 25 = 45
      • Combination 3: 10 + 15 + 20 = 45
  3. Example 3:
    • Problem: Select numbers that add up to 75.
    • Solution:
      • Combination 1: 25 + 50 = 75
      • Combination 2: 30 + 45 = 75
      • Combination 3: 20 + 30 + 25 = 75

🎉4. Tips for Finding Combinations

  • Start Small: Begin with smaller numbers and add up gradually to reach the target sum.
  • Use Addition Facts: Recall basic addition facts to find combinations more easily.
  • Write Down Combinations: List out different combinations to visually check if they meet the target sum.

🎊5. Practice Exercises

  1. Problem 1:
    • Choose numbers that sum to 35.
    • Possible Combinations: 10 + 25, 20 + 15, 5 + 10 + 20
  2. Problem 2:
    • Find numbers that add up to 50.
    • Possible Combinations: 15 + 35, 20 + 30, 25 + 25
  3. Problem 3:
    • Select numbers that sum to 100.
    • Possible Combinations: 50 + 50, 40 + 60, 20 + 30 + 50

Learn with an example

▶️ Choose two numbers from the box to complete the addition number sentence. [ 1, 3 , 6, 9 ]

____ + ____ = 15

Try 1. What number can you add to 1 to get 15?

1 + 14 = 15
14 is not in the box.

Try 3. What number can you add to 3 to get 15?

3 + 12 = 15
12 is not in the box.

Try 6. What number can you add to 6 to get 15?

6 + 9 = 15
9 is in the box.

The addition number sentence is 6 + 9 = 15.

▶️ Choose two numbers from the box to complete the addition number sentence. [ 4, 7, 41, 89 ]

____ and ____ have a sum of 45.

Look for numbers in the box that are less than 45.

Try 4. What number can you add to 4 to get 45?

4 + 41 = 45
41 is in the box.

The numbers 4 and 41 have a sum of 45.

🔥Choose two numbers from the box to complete the addition number sentence.

1 6 9 68

____ + ____ = 10

Look for numbers in the box that are less than 10.

Try 1. What number can you add to 1 to get 10?

1 + 9 = 10
9 is in the box.

The addition number sentence is 1 + 9 = 10.

Let’s practice!