Unit#5-15

Learning Outcome

At the end of this lesson, you will be able to:

• start to understand the problems with negative numbers

Review

• remember, Binary Numbers place values are:

  • 8, 4, 2 ,1

Lesson

• what do we do about negative numbers?

  • everyone's first reaction is to use the first bit as a "sign" bit

  • this is called "signed magnitude"

  • since we only have 1s and 0s, we can not use a "+" or "-" sign

    • so let's use a "0" = "+" and "1" = "-"

• good idea but there is a problem:

  • if this is 3 -> 0011

  • then this is -3 -> 1011

  • what happens when we add them?

Activity

• nil

Daily Assignment

• complete the attached worksheet