Final answer:
To calculate the sum of characters represented by numbers, add their numerical values while considering their signs: positive with positive, negative with negative, or apply subtraction rules for different signs. Subtraction is handled by changing the sign of the subtracted number and proceeding with addition. Rounding of significant digits depends on whether the first dropped digit is greater or less than 5.
Step-by-step explanation:
The sum of a set of characters represented by numbers is determined by adding together the assigned numerical values in accordance with certain rules. When two positive numbers are added, the result will have a positive sign. Conversely, adding two negative numbers gives a result with a negative sign.
If the numbers with opposite signs are added, one must subtract the smaller number from the larger and assign the sign of the larger number to the result. For example, -5 + 3 equals -2 because 5 is larger than 3, so the difference is 2 with the sign of the larger number, which is negative in this case.
For subtraction, we essentially change the sign of the number to be subtracted and then follow the rules of addition. For instance, to subtract 3 from 5, we change the 3 to -3 and add it to 5, which gives us 5 + (-3) = 2. This method simplifies the subtraction process into an addition problem.
When rounding significant digits, if the first dropped digit is 5 or greater, the final answer is rounded up. If the first dropped digit is less than 5, the final answer is rounded down. In practice, this affects how we report the final result of calculations where precision is limited.