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You may need a for loop within a for loop for this. Please follow the steps below.

```# declare a total_sum variable and set it equal to zero
total_sum = 0

# iterate over travel_expenses list. On each iteration, t_e is a sublist within travel_expenses, right?
for t_e in travel_expenses:
# now, iterate over t_e. This will give you each and every element within a sublist on that iteration.
for i in t_e:
# add each element, i, to total_sum.
total_sum += i

# then, you will have every element summed up.

#Yes, it is 147.25.
print(total_sum)
```

I hope this helps.

Make sense. Thanks

```travel_expenses = [
[5.00, 2.75, 22.00, 0.00, 0.00],
[24.75, 5.50, 15.00, 22.00, 8.00],
[2.75, 5.50, 0.00, 29.00, 5.00],
]

print("Travel Expenses:")
week_number = 1
running_total = 0
for week in travel_expenses:
weekly_sum = sum(week)
running_total += weekly_sum
print("* Week #{}: \${}".format(week_number, weekly_sum))
week_number += 1

print("Your current total expenses are {}".format(running_total))
```