Q&A #1154

Teachers' Lounge Discussion: Front End Estimation

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From: Julian <jek_9@yahoo.com>
To: Teacher2Teacher Public Discussion
Date: 2001010422:35:28
Subject: Give me a break!

"5.45 +6.49, 7.48, 2.42, and 1.49, rounding would get me the answer to
5 + 6 + 7 + 2+ 1, or 21. 
   "With front end estimation I would add the whole numbers, getting
$21, and then refine that estimate by noting that there are about
$2.50 more there, for an estimate of $23.50.  The actual sum is

I can't believe this came from a Swarthmorian-LOL.  You're not
explaining front end estimation.  If I were rounding, I would also
round the pennies afterwards (especially if they were in the 50 cents
range).   You have to do better than that Gail. Regular rounding would
get me an answer of between 23 and 24 dollars too. (21+2.50)

Whoever invented front end estimation should be locked up and put
away. The 4th grade teachers have a hard time explaining it, and worse
yet the students don't have a clue. Rounding should be the only method
taught.  It's simple, direct and the students-understand the concept.

The reference you put on top is exactly the way I told my son to do a
problem.  It would have been marked WRONG because 21 was the answer
the teacher would have been looking for! Altough the answer given of
23.5 was more accurate, and was achieved more easily through rounding.

Rounding(5.50+6.50+7.50+2.40+1.50)=$23.40(rounding from cents column).

I tell my son the smaller the number the more accurate the rounding
has to be. 999,930 = 1,000,000  .04 =.05   In short, I agree with the
PTA member!


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