In the 1400s, European merchants used positive and negative numbers to label barrels of...

In the 1400s, European merchants used positive and negative numbers to label barrels of flour. For example, a barrel labeled +3 meant the barrel was 3 lb overweight, whereas a barrel labeled meant the barrel was 5 lb underweight. If the following numbers were found on 100 lb barrels, what was the total weight of the barrels?