Arithmetic Grade Three

Lesson One hundred and six: Rounding and Multiplying

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

Rules for rounding to the nearest 10:

  1. If the number in the ones column is 4 or less round down. Example: 42 -> 40.
  2. If the number in the ones column is 5 or more round up. Example: 45 -> 50.
Here's another sample problem: 
     
      Original          Rounded 
       Problem          Problem
         86      --->     90
        x 4      --->    x 4
        ----             ----
              ANSWER:    360

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