218 Appendix F
Now, what if someone took away those three bills for $2? Th at is
minus 3 bills or amounts of minus $2. Th at means you have $6
more than before the bills were taken away. You could write that as:
–3 × –2 = +6.
I tell students not to worry about the concept too much. Th ey don’t
have to understand it immediately. I tell them we will just keep using
the concept and I will keep explaining it until they do understand.
It is not a race to see who can understand it fi rst. I tell the students
that understanding will come.
You can give examples of forward speed and head wind. Forward
speed is positive; head wind is negative. Adding and subtracting
positive and negative numbers is no big deal. You add positive; you
subtract negative. It is just a matter of recognizing which is which.
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brent
(Brent)
#1