A yellow counter is +1 and a red counter is −1. Which addition, with its answer, do the two groups of counters show?

When two integers have **different signs**, subtract the smaller absolute value from the larger one and keep the sign of the larger absolute value. So 7 + (−3) = 4 (|7| > |−3|, so the answer is positive 4), and (−7) + 3 = −4 (|−7| > |3|, so the answer is negative 4). On the number line: a positive number moves right, a negative number moves left — they partially cancel.