? about a math concept

[sbgrace]

A few units ago, my son studied mean/median/mode/range. This is a Singapore based program.

 

When the curriculum gave him a problem such as: Sue averaged $40 per day with craft sales. If she made $38 on Monday, $42 on Tuesday, $36 on Wednesday, and $39 on Thursday, how much did Sue make on Friday?

 

It was the only thing in the entire unit that threw him. But it did. We worked on it, and he could consistently solve it. I wasn't ever completely sure he internalized why, but we tried to explore that with real life examples and number manipulation. He seemed to understand.

 

We did a review unit this week. He could not solve this sort of problem at all. Poor recall in math is unusual for him. We went back through it and why it works. He's fine now.

 

I do not think he'll be ok if I check back in a month though. I don't think it's clicking somewhere it needs to click. I feel he needs to somehow internalize the why better and maybe he'll remember the how.

 

How can I better teach this?

 

Or should I just move along and check back in a month, reteaching as needed?

[kiana]

Could he do it and understand it when there were only two things to average? i.e. Jeremy got a 54 on his first math test. After his second test, his average was 62. What did Jeremy make on his second math test?

[Arcadia]

Mean/median/mode/range is covered as a topic once a year, every year so far and would be all the way to high school statistics.  It is such a stand along topic that I won't be worried about recall.  However it is the terms that throw my younger one off as in he could not remember the definitions.

So for the same word problem, if I ask him to compute the average (mean), middle term (median), most frequent number (mode) he can do it very fast.   Ask him what is another name for average and he can't answer. By the time he went through SM5B, the terms did sink into his head. He didn't have problem with the word range.

My older did not need the word substitution.  However after a long time of not doing statistics, he will sit for awhile and figure out in his head the definition for mean/mode/median before he does the questions.

 

[Cosmos]

Mean/median/mode/range is covered as a topic once a year, every year so far and would be all the way to high school statistics.  It is such a stand along topic that I won't be worried about recall.  However it is the terms that throw my younger one off as in he could not remember the definitions.

 

These are sort of silly, but I taught my son these little mnemonics --

 

median is the MIDDLE (sounds similar)

mode is the MOST (sounds similar)

and the mean is the mean one because you have to do a calculation to find it :001_rolleyes:

 

Anyway, it helped him remember.

 

OP, have you tried displaying the data on a graph. If he sees $38 on Monday, $42 on Tuesday, etc. and compares that to the average of $40, does that help at all? He would see that Monday was $2 below average, Tuesday was $2 above average, and so on. One way to think of it visually is that you can pluck some quantity off the large data points and redistribute them until every column is the same height.