1. The problem is to solve an equation or expression and include the units in the final answer. 2. When solving problems involving units, always carry the units through each step of the calculation. 3. For example, if you are calculating distance, speed, or time, write the units explicitly with the numbers. 4. Suppose the problem is to find the speed given distance and time: speed $= \frac{\text{distance}}{\text{time}}$. 5. If distance $= 100$ meters and time $= 20$ seconds, then speed $= \frac{100\text{ m}}{20\text{ s}}$. 6. Simplify the fraction: $$\frac{100\text{ m}}{20\text{ s}} = \frac{\cancel{100}\text{ m}}{\cancel{20}\text{ s}} = 5\text{ m/s}$$. 7. The final answer is speed $= 5$ meters per second (m/s). 8. Always include the units in the final answer to clearly indicate the quantity measured.