The amount you owe can be calculated as the total expenses minus the total earnings. It is the opposite to the amount you got, for example, in a bank account.
In this case, the total expenses are $2345 and the total earnings are $1459. As the expenses are larger than the earnings, we have a positive value for the debt.
Then, we can calculate the total debt as:
NOTE: it can be also calculated as the negative value of the account balance (earnings minus expenses).
Answer: the amount owed in bills is $886.