The book I am working with makes a big deal about knowing which way the sign goes in operations of addition and subtraction.

I would say just try to work it out logically in your mind

3+4 = 7

3 + -4 = -1

This can get confusing when you subtract a negative number

3 - -4 = 7

This is probably one case where memorization works since it is hard to intuitively see that subtracting a negative number is the same as adding it. So just remember that when you subtract a negative number to just change the sign to addition.

## Monday, March 16, 2009

Subscribe to:
Post Comments (Atom)

## No comments:

Post a Comment