Which description best matches the steps used to add signed numbers?

• A. Add all numbers ignoring the signs, then apply the sign of the larger magnitude.
• B. Convert all numbers to decimals and add them.
• C. 1. Add all numbers having a plus sign. 2. Add all numbers having a minus sign. 3. Of these answers, subtract the smaller from the larger. The sign of the answer will be the sign of the larger number.
• D. Subtract positives from negatives only.

Answer: (C)

When adding signed numbers, you combine by their signs and magnitudes. The reliable method is to separate the numbers into positives and negatives, sum all positives to get a positive total, sum all negatives to get a negative total, then combine the two totals by subtracting the smaller magnitude from the larger and using the sign of the larger magnitude. This captures the idea that adding numbers with the same sign increases magnitude, while opposite signs subtract magnitudes and leave you with the sign of the larger one.

For example, consider +7, -4, -2, +3. Positives sum to +10, negatives sum to -6. Subtracting gives 10 - 6 = 4, and the larger magnitude was positive, so the result is +4. This approach always yields the correct result, even when the signs oppose and the magnitudes differ.

Other descriptions misstate the process: simply ignoring signs and then applying the sign of the larger magnitude can give incorrect results (for instance with 5 and -8 it would produce -13, while the actual sum is -3). Converting to decimals isn’t describing how signed integers are added, and subtracting positives from negatives only ignores when positives outnumber negatives.