When adding two numbers with the same sign,      1. add the absolute values, and      2. write the sum (the answer) with the same sign as the numbers. • (+4) + (+7) = +11 • (-5) + (-8) = -13 • (4) + (6) = 10 When adding two numbers with different signs,      1. subtract the absolute values, and      2. write the difference (the answer) with the sign of the number having the larger absolute value. • (+5) + (-8) = -3 • (-10) + (+15) = +5 • (-20) + 17 = -3
The slang "naked" number is the number without its sign. A naked -8 would be 8 (or the absolute value of -8).

 Subtracting Signed Numbers: Examples:
 When subtracting two numbers, change the sign of the number being subtracted and then follow the rules for adding signed numbers. (Subtracting a number is adding its opposite.) • 8 - (-3) = 8 + (+3) = 11 • -10 - (-8) = -10 + (+8) = -2 • -8 - (+6) = -8 + (-6) = -14 • 13 - 8 = 13 + (-8) = 5

 Multiplying or Dividing Signed Numbers: Examples:
 When multiplying two numbers,      • If the signs are the same, the result is positive.     • If the signs are different, the result is negative. If you have a long series of multiplications of negative values, remove the negative signs in pairs.       (-2)(-3)(-1)(-1)(-5)(-1)(-2) =(2)(3)(1)(1)(5)(1)(-2) = -60 • (+3) x (+9) = +27 • (-6) x (-8) = +48 • (-5) x (+6) = -30 • (+8) x (-2) = -16