Answer: -9
Step-by-step explanation: When your adding and subtracting positives and negatives, it's a good idea to use a number line to visualize what's going on.
When you're simplifying a problem like (+4) + (-13) we start at zero and +4 moves us 4 units to the right along our number line.
From there, -13 then moves us 13 units back to the left so we end up at -9.
Image provided.
Therefore, (+1) + (-13) = -9
