Select all true statements about the sum -7 + 12 + (-9) + 4.
The negative addends together contribute -16.✓Правильный ответ
The positive addends together contribute 16.✓Правильный ответ
The sum is 0.✓Правильный ответ
The sum is 32, since all four magnitudes combine.
The sum is -32, because the negative addends are written first.
Объяснение
Gathering like signs puts seven and nine on the left and twelve and four on the right, two contributions of equal size pulling opposite ways, so they cancel completely. Adding the four magnitudes instead drops the signs during the gathering and turns two opposing moves into one long move in a single direction.