A negative minus a negative is equal to another negative number, a positive number or zero, depending upon the numbers in the equation. Subtracting a negative number from another negative number is the same thing as adding a positive number.
If the negative number being subtracted is the same as the number from which it is subtracted, the answer is zero. For example, 5  (5) = 0. If the negative number being subtracted is greater in value than the negative number from which it is being subtracted, the answer is negative. For example, 10  (8) = 2. If, however, the negative number being subtracted is less in value than the negative number from which it is being subtracted, the answer is a positive number. For example, 10  (12) = 2.
You get a positive subtracted number.
http://wiki.answers.com/Q/Negative+7+minus+a+posit...

14  (3) The double negative cancels out and forms a positive.14 + 3 = 11 ■.
http://wiki.answers.com/Q/What_is_negative_fourtee...

Sinner.
http://wiki.answers.com/Q/What_is_another_word_for...

18. Subtracting a positive number has the same effect as adding a negative.
http://wiki.answers.com/Q/What_is_negative_12_minu...
