Moving cost: How do I figure mileage paid during a move. It is 0.18 per mile (100 miles 1 way) but several trips were made. How to figure cost? Is it $18 per 1 way trip?

We moved 100 miles (1 way) for job related move. We meet the criteria for deduction for moving but I don't know how to figure gas cost. We took several trips to move personal items in addition to the moving company. I don't have receipts for the gas. I understand it is 18 cents per mile I can claim but does that mean for both coming and going to new home? Each trip?