Expressing Your Math in Writing

This summer I signed up on Yahoo! Answers forum. On a regular basis I get on the computer and answer questions that other people are asking. I frequently go to the "mathematics" and "homework help" sections. As I write this, I currently have 2461 points on that forum, a distinction that places me just 39 points away from being a level 4 member. About 31% of my answers have been voted or designated as "best answers".

It has been a rewarding experience. When I help a person with their homework, I try to explain the steps, definitions, and processes of how to do the assignment, rather than just telling the answer. This is something I do in the classroom all the time, but now I am doing it in writing. That's not so different from what we sometimes ask our students to do--express their math processes in writing. The avatar shown above is my avatar from Yahoo! Answers.

Here is a question that was recently asked:

Find the average......................?
The 45 students in a class each recorded the number of whole minutes, x, spent doing experiments on Monday. The results are
total x= 2230

Find the mean number of minutes the students spent doing experiments on Monday.

^that one i can do, but its the next one i dont know

two new students joined the class and reported that they spent 37 minutes and 30 minutes respectively.
calculate the new mean including these two students.

Here is my answer:

To find the mean or average, divide the sum of the data by the number of individual data entries -- so in the first problem 2230/45 = 49.5 or 50 when rounded.

In the second problem add the two new data values to the previous sum (2230 + 37 + 30= 2297) and divide by the number of data values (45+2=47). So 2297 / 47 = 48.8 or 49 when rounded.



Math and Writing

Sometimes kids complain when we ask them to write in math class. They feel that writing is not and should not be part of math. But teachers reply that mathematicians need to know how to write -- after all what good is all of their math if they can't communicate their findings? Participating in the Yahoo! Answers forum has helped me sharpen my own writing skills as they specifically pertain to math.