Rounding

Arithmetic Grade Three

Lesson Thirty-three: Rounding and then Subtracting

Before we get too far into this lesson, let's review a little:

Rules for rounding to the nearest 100:

If the number in the tens column is 4 or less, then round down. (Example: 544 -> 500.)
If the number in the tens column is 5 or more, then round up. (Example: 550 -> 600.)

Here's a sample problem for you:

     
      Original          Rounded 
       Problem          Problem
         816      --->     800
        -582      --->    -600
        -----            ------
              ANSWER:      200

Here's another example for you:

     
      Original          Rounded 
       Problem          Problem
         285      --->     300
        +147      --->    +100
        ----             ------
              ANSWER:      200

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