math Did I do it right?

Use front-end estimation to find the value of the expression. I do not understand (without adjustment)

687 - 239 (without adjustment)

is this right?

600 + 200= 800 + 126=926

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asked by Bart
  1. If your problem is 687 - 239, it makes sense to me to do it this way:

    700 = 200 = 500

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    posted by Ms. Sue
  2. Correction:

    700 - 200 = 500

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    posted by Ms. Sue
  3. Right it was subtraction. So what does "without adjustment" mean?

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    posted by Bart
  4. I'm not a math teacher -- but I assume you don't need to adjust for the small differences between your estimated numbers and the actual numbers.

    This site may explain it.

    http://mathforum.org/library/drmath/view/65415.html

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    posted by Ms. Sue
  5. Thank you

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    posted by Bart

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