Which spanner size is the smallest among the following options?

The choice of 3/8 as the smallest spanner size is correct, as it represents a measurement that is less than 11/16, 3/4, and 13/16. In fractional measurements, when comparing sizes, you look at the numerators in conjunction with the denominators.

3/8 translates to 0.375, while the other options convert to values greater than 0.375. Specifically, 11/16 is approximately 0.6875, 3/4 converts to 0.75, and 13/16 equals about 0.8125. Therefore, 3/8 is indeed the smallest size in this list, making it the correct choice.

Understanding how to convert these fractions into decimal form can be critical when assessing different spanner sizes to determine which is the smallest or largest. This process emphasizes the importance of numerical comparison in practical mechanical applications.