Your assignment is to explain
addition (base 10, using the standard American-school algorithm). Specifically, you must:
- Make up a 3-digit addition problem, for which you must exchange
twice
(ones for tens and tens for hundreds).
- Show how to solve your addition problem by:
- showing what to do with manipulatives (base 10 blocks or stamp
game tiles)
- showing how to record your manipulative work in the usual
pencil-paper way
- explaining in words what you are doing and why, so that the
manipulative work and the pencil-paper work fits together and makes
sense
Examples to watch: me explaining
this. A student explaining this. Another
student explaining this.
You have the option to do this
- On paper, with the manipulatives, the numbers, and the words you
would say written out in full. No points for artistry, but don't
skip steps! OR
- On video, using these resources:
- Use the manipulatives in one of these SMART Notebook files: Base 10 blocks; Stamp Game. SMART Notebook is
installed on the computers in WEB. You can also use SMART Notebook Express from your home computer
- Record yourself using Screencast-o-matic, or, if you are using your home computer, you might want to install and use Jing.
- Make sure you have a working microphone (make a quick test
video to check it)
Tips for getting a good grade:
- Choose good numbers:
- Choose numbers that will give you a good variety of sums when
adding
- Make sure your numbers fit the criteria for the problem
(exchange twice)
- As much as possible within the guidelines above, make sure that
all of the digits are different--this makes it easier to keep track of
what's going on (if there's more than one 4x5 in your problem, there's
a confusion about which is which, and indeed, if you are adding, it is
ideal to not have sums of 11, since then it is harder to distinguish
between the tens and ones place)
- Use correct language:
- place value language; know what place value you are working
with, and name it correctly. Name place values wherever it is not
undesirable to do so.
- parts of an operation: the important words for this problem are
addend and sum. The numbers you are adding are addends. The
number you get as a result of adding is the sum
- Don't use "borrow" or "carry", instead use words like: trade,
exchange,
rename, regroup and/or record
- Explain the trading steps explicitly. For example: Now we
trade 1 hundred for 10 tens, and that's a fair trade because 100=10
tens.
- Go from concrete to abstract
- If you have both a manipulative and a number way of showing the
algorithm, do each step first with the manipulative, and then with the
numbers, and
- explain each step in the number work as a way of recording
what is happening with the manipulatives
- Make the connections step by step--don't wait until you have
done the whole problem with the manipulatives and then make the
connections: do a step with the manipulatives, and then the same thing
with the numbers. (My husband describes one of his friends'
masters thesis as dropping a wall on the reader one brick at a
time. I want you to drop an algorithm wall, very carefully, on
your listener, one brick at a time.)
Tips for getting the technology to work:
- Here is a vid of me using
Screencast-o-matic (on a Mac--the computers with microphones in WEB
are Macs). If screencast-o-matic doesn't work in WEB, try a
different web browser (Firefox, Explorer and Safari are web
browsers). If screencast-o-matic doesn't work on your personal
computer, try updating your Java.
- Here is a vid of me using SMART
Notebook
- If you are doing this on your own computer, I recommend starting
with screencast-o-matic, and if that does not work the way you would
like it to, that you next check out Jing
.
- When you are done, you should have a file on your computer
(hopefully somewhere you can find it--if you are in WEB, and you can't
find the file, get one of the technology helper people to show you how
to search for it by name). The file should be something.mp4 if
you made it and exported it with Screencast-o-matic. If you used
Jing, the file name should be something.swf. Upload this file to
the D2L dropbox: addition explanations.