Friday, November 7, 2008

An Old Mom Fails New Math


It was bound to happen, I just didn't think that it would happen so soon! I can no longer help my daughter with her math homework, and she's only in 4th grade. I have long considered myself to be of reasonable intelligence, so this is quite a blow to my self-esteem.

So, to lay the background, yesterday, my daughter had a timed math test on division facts. Two answers were marked as being incorrect. Both were problems in which a number was being divided by zero.

8/0 = She answered "0." 5/0 = She answered "0." Both were wrong answers.

I asked her, "What IS the correct answer?" She said that she didn't know. Hmm, I swear that when I was a kid we were taught that any number divided by zero results in an answer of 0.
It turns out that little "rule" only applies to multiplying by zero. Any number multiplied by zero results in a product of 0.

According to Wikipedia, it's not a "and vice versa" situation. Apparently, numbers cannot "really" be divided by zero, and the answer should be "undefined." So, my question is, "Was she supposed to write "undefined" on her TIMED division quiz?" Writing out the word would take up a good deal of the 3-minutes of time, wouldn't it? Is there some sort of symbol that is used to denote that the answer is "undefined?" To my math-challenged brain, this seems like a trick question.

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Part two of my math failure.

Daughter did a math assignment in which she was asked to measure the distance between several cities in a country. She used an old wooden inch ruler that I have had for years! She measured and recorded the inches, and then she calculated with the map's scale how many miles the measurement equated to. (1 inch = 200 miles)

She completed her homework and I checked her work. Her inch measurements looked kosher to my own measurements. Her calculations from inches to miles looked correct, too.

Yesterday, the homework was returned. She scored 12 out of 16 on the assignment. We remeasured. We recalculated miles. Measuring with inches seems to have changed since I went to school, or my ruler is way out of whack. We sent back the homework sheet, with our antiquated ruler, to school today.

Just so you know, if you try to reach me today, I may be attending 4th grade math to relearn measuring skills. Perhaps I should just learn that this is her father's area of expertise and not set myself up for feeling inadequate!

After reviewing her the Math portion of her WKCE practice booklet last night, I can only be glad that I'm not being tested in that arena. Which leads me to believe that my math skills are not among the attributes that inspire my daughter! (see previous post)

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