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Addition strategies

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Intros
Lessons
  1. Introduction to Addition Strategies:
  2. Mental math and sums of 10
  3. Addition strategy #1: friendly numbers with adjustment
  4. Addition strategy #2: creating friendly numbers using addends
  5. Addition strategy #3: adding on from left to right
  6. Addition strategy #4: adding by counting on
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Examples
Lessons
  1. Adding by grouping sums of 10
    Add by pairing up sums of 10. Circle the pair and fill in the blanks.
    1. 8 + 5 + 2 = ____
      10 + ____ = ____
    2. 1 + 7 + 3 = ____
      10 + ____ = ____
    3. 6 + 9 + 4 = ____
      10 + ____ = ____
  2. Adding by 9 strategy
    Add 9 by: adding 10 first, then taking 1 away. Fill in the blanks.
    1. 7 + 9 = ____
      7 + 10 = ____ - 1 = ____
    2. 14 + 9 = ____
      14 + 10 = ____ - 1 = ____
    3. 38 + 9 = ____
      38 + 10 = ____ - 1 = ____
  3. Adding by 8 strategy
    Add 8 by: adding 10 first, then taking 2 away. Fill in the blanks.
    1. 7 + 8 = ____
      7 + 10 = ____ - 2 = ____
    2. 16 + 8 = ____
      16 + 10 = ____ - 2 = ____
    3. 54 + 8 = ____
      54 + 10 = ____ - 2 = ____
  4. Adding using friendly numbers with adjustment
    Add by changing one number into a "friendly" number and adjust. Fill in the blanks.
    1. Addition Strategies
    2. Addition Strategies
    3. Addition Strategies
  5. Adding by making friendly numbers with given addends
    Add: make "friendly" numbers using given addends. Fill in the blank.
    1. Addition Strategies
    2. Addition Strategies
    3. Addition Strategies
  6. Adding on strategy
    Use the method of adding on from left to right.
    1. 553 + 385 = ____
    2. 730 + 291 = _____
    3. 664 + 148 = ____
  7. Counting on from the first number
    Add by counting on from the first number
    1. 104 + 693 = ____
    2. 827 + 335 = _____
    3. 568 + 429 = ____
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Practice
Topic Notes
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In this lesson, we will learn:

  • The addition strategies of: (1) using friendly numbers with adjustment, (2) creating friendly numbers using addends, (3) adding on from left to right, and (4) adding by counting on
  • Understanding adding by 9

Notes:

  • Method 1: change into a "friendly" number and then adjust (by subtracting)
    • Round one of the addends to the nearest multiple of 10
    • Then adjust by taking away how much you rounded up by to get the answer
Addition Strategies
  • Method 2: make a "friendly" number using the addends
    • Use the numbers that were given for the addition equation
    • Move values from one number to the other number to make a multiple of 10
Addition Strategies
  • Method 3: adding from left to right
    • Add by going through one place value at a time
    • i.e. hundreds of 1st # + hundreds 2nd # + tens of 1st # + tens of 2nd # + . . .
Addition Strategies
  • Method 4: adding by counting on
    • Start with the first number, then add the second number one place value at a time
Addition Strategies