Please help and give a explanation I will give brainliest and 25 points

Answer:
Addition: -1 + -3 = -4
Subtraction: (-4) - 5 = -10
Step-by-step explanation:
Since adding a positive makes a negative number stay negative, it equals -4.
Then by subtracting a negative with a positive (5), the number stays negative once again, which then equals -10.