Ana's math homework was working with thermometers

[conuly]

The first problem had a cut-out segment of a thermometer with the tens marked and the ones done as lines. Ana was supposed to "estimate" the location of ten lettered spots on the thermometer. So she did estimate, but very badly. I'm not sure how she came up with some of the numbers. I looked at it, erased everything, and asked her what the lines meant. "They didn't say I could count!" Well, she can count, but her estimation skills aren't that great. We went over that as well, and I'm not sure which set of answers was really asked for.

Then she was supposed to "use a thermometer" (an actual one, the little diagram didn't have the correct range) to "find the change" in various temperatures. "I can't do that, we don't have a thermometer!" Well, we do, but it's a digital one and useless for this purpose. If I want to find out how warm it is outside, I don't want to squint at some mercury, I just turn on NY1, which has the added bonus of telling me how warm it's going to be. Or I open the window and wave my arm outside, same difference. Given that some of these problems went into negative numbers, which she hasn't been taught yet, the least they could've done was included a number line! Back in first and second grade number lines were included ALL THE TIME and hindered her from actually memorizing simple facts, but now that they're useful again they just assume we all have thermometers hanging around for this purpose?

I said "Ana, just subtract." "I'm supposed to use a thermometer!" "Ana, listen. What's the difference between 56 apples and 24 apples? 32, right? It's the same thing." We managed to get through the ones with negative numbers fairly competently as well, and she immediately grasped that you go down to zero and then add the under zero number. She had learned that much. Argued with me about putting a plus or minus in front of the answers, but I told her that otherwise the answers were meaningless. "My teacher didn't tell us that!" Well, I'm sure she meant to, and you rarely get in trouble for doing more, so hop to it.

Then, the kicker, she had to choose between two answers for approximate temperatures of various things - a lake, an ice cream, hot tea, and something else. Some where in Fahrenheit and others in Celsius. Well, Ana DOES know the boiling and freezing points of water in Celsius, which I pointed out is also called centigrade because centi means a hundred (never too often to make the point that we can work out what words mean by analyzing them). But she didn't know human body temperature, or ANY markers in Fahrenheit. Shouldn't this be down pat before they start guessing and estimating other things? Shouldn't some of the questions be reviewing the facts that let us know what answers are reasonable before they're thrown into the deep end? There is nothing wrong with this sort of work, but shouldn't they have the background solidified FIRST? Why did I have to tell her these things?

Comments

[oloriel.livejournal.com]

Perhaps Math Teacher assumes that Biology Teacher or Physics Teacher already taught them about the different temperature scales, and never bothered to ask whether they really already knew that?

(Of course, if they don't have separate science classes, this point is moot. In which case the answer might be "The teacher is just doing this by the book, and the book is obviously not all that good." Wait, actually that's the answer either way...)

[conuly]

She's in the fourth grade. Science is integrated, and probably should've discussed thermometers by now, but it's a bit much for the textbook to simply assume it has.

[oloriel.livejournal.com]

Depends. Maybe the same publisher is also publishing a 4th-grade Science textbook which explains thermometers and the history of different systems quite early on, so by the time a class reaches these math problems, they'd definitely know all that. The people who wrote the textbook probably expected that a responsible teacher would ask the kids whether they knew about thermometers, and if they didn't, would explain the basics...

... yeah, maybe that was a bit much to assume. *ducks*

[pne.livejournal.com]

the least they could've done was included a number line! Back in first and second grade number lines were included ALL THE TIME and hindered her from actually memorizing simple facts, but now that they're useful again they just assume we all have thermometers hanging around for this purpose?

I wonder whether that's a product of using a syllabus that's several decades old and hasn't been updated to cope with changes in people's customs? (Such as digital thermometers.)

[conuly]

Not impossible, but publishers tend to revamp curricula often in the US, so how this slipped through the cracks....

Come to think of it, Eva's book last year (Everyday Math, and you can google for more info on that) was big on using pictures of thermometers instead of number lines to practice skip counting (counting by fives, tens, or twos. Who the heck counts by twos when reading a thermometer?)

[marveen.livejournal.com]

Depends on if your thermometer has the lines in intervals of two. (My mother's candy thermometer has intervals of two, so if the recipe calls for 246 degrees, you have to look at 240 and count up by twos to see if it's ready.)

[conuly]

Okay, that answers that question, but raises so many more, like "how many households have candy thermometers?" and "are kids supposed to be familiar with those?" and "aren't those, too, largely digital nowadays?"

Though that information is good to have. The only candy I make is never fail fudge, which I can make with a timer and a cup of cold water to check for the soft ball stage, but I'm aware that anything more ambitious requires more precision. I just didn't think it through : )

[houseboatonstyx.livejournal.com]

I'm glad they're at least being taught estimation (or something that goes by that name). In the 1950s 'estimation' was something my grandmother did that the teachers thought was old fashioned and ignorant.

[conuly]

How funny! When I was young we were formally taught how to round up or down to the nearest whatever, just like Ana has been.

[houseboatonstyx.livejournal.com]

There was more to the old kind. You started by seeing that the answer would be a number somewhere between, say 300 and 400. Then you narrowed it down as far as needed.

I wish I could remember the details. For addition, instead of starting at the left end and 'carrying' the 10s and 100s, you started with the larger numbers and added them, then the next largest, and so on.

Okay, maybe for addition you would round up both numbers and add them, to get an upper limit. Then maybe round both down and add them to get a lower limit.

There was an equally simple method for long division, too.