Dimensional analysis is another way of doing unit conversions. In that method, we form conversion ratios and then cancel units (similar to how we cancel common factors when multiplying fractions). In the following example, I'll convert 45,760 yards to miles using the knowledge that 1 yard is 3 feet and 1 mile is 5,280 feet.
\(\displaystyle \frac{45760\text{ yard}}{1} \;\times\; \frac{3\text{ foot}}{1\text{ yard}} \;\times\; \frac{1\text{ mile}}{5280\text{ foot}}\)
\(\displaystyle \frac{45760\;\cancel{ yard}}{1} \;\times\; \frac{3\;\cancel{ foot}}{1\;\cancel{ yard}} \;\times\; \frac{1\text{ mile}}{5280\;\cancel{ foot}}\)
\(\displaystyle \frac{45760\;\times\;\cancel{3}^1\;\times\;1\text{ mile}}{1\;\times\;1\;\times\;\cancel{5280}_{1760}}\)
\(\displaystyle \frac{45760\text{ mile}}{1706}\;=\;26\text{ mile}\)