Final answer:
The sum of 12 and its opposite, which is -12, is zero. This is due to the additive inverse property, where a number added to its opposite results in zero.
Step-by-step explanation:
The sum of 12 and the opposite of 12 is calculated by adding 12 to -12. According to the rules of arithmetic, when you add two numbers with opposite signs, you subtract the smaller number from the larger one, and the answer takes the sign of the larger number. However, in this case, since the two numbers are identical in magnitude, their sum is zero.
To illustrate:
12 + (-12) = 0.
The sum is zero because when a number is added to its opposite, the result is always zero. This is an example of the additive inverse property, where a number plus its additive inverse (the opposite) equals zero. This concept is fundamental in mathematics and is used to solve various equations and problems.