Mathematics Chapter 1 - Directed Numbers

  •  Numbers are said to be directed by the sign they have in front of them. Some examples are -3, +4, -7, +5 and so on.
  • It should be noted that positively signed numbers are normally written without the + sign in front. Therefore +4 is written as 4, +131 is written as 131.
  • To understand directed numbers, always keep in mind the following simplenumber scale:


  • Always start from 0, then if you have a positive number always move to the right in steps equal to the number (for example +4: start from 0 and move 4 steps to the right). Similarly, always move to the left for negative numbers.
  •  When it comes to multiplying directed numbers, the signs must be considered  first and then the numbers. 
    • For example -3 x -4 is worked in 2 steps. First multiply the signs - x - and you get a +. Then multiply the numbers and you get 12.

    • When dividing signed numbers similar signs cancel out and give a + sign to the result. Different signs always give a sign.

    BASIC RULES: 

    ADD a POSITIVE means ADD                               + +3 = + 3
    ADD a NEGATIVE means SUBTRACT               + -3 = - 3
    SUBTRACT a POSITIVE means SUBTRACT    - +3 = - 3
    SUBTRACT a NEGATIVE means ADD                - 3 = + 3