Add the number of domestic ships inspected in 1968 to the number of foreign, then multiply the total number of ships inspected by 500 tons to get the total tonnage. Approximately 11,000 domestic ships were inspected in 1968, and approximately 5,000 foreign ships, for a total of about 16,000 ships. The tonnage per ship was 500 tons, so the total tonnage was 16,000 $\times 500$. Since 500 is one-half of 1,000 , we can simplify our arithmetic by doubling 500, and multiplying 16,000 by $\(\frac{1}{2}\)$. This gives us a total of $\(1,000 \times 8,000=\)$ $\(8,000,000\)$ or 8 million tons.