Answer:
1. It helps in representing numbers that are below or above zero.
2. It gets confusing at times, especially when dealing with negative signs because they can look abstract or non-realistic.
Explanation:
1. Arithmetic with signed numbers is basically the addition of the positive (+) and negative (-) signs in front of numbers. It helps in providing a basis for evaluating if the number is less than or equal to zero. Number lines serve as a helpful guide where zero is centralized and numbers on the right of zero are positive numbers and numbers on its left are negative numbers.
2. It gets a bit confusing, especially when using negative numbers in real-life examples. For example, it is confusing to say that 'John has -2 books'. It is actually hard to imagine such a case.