To convert between units, you're usually given one measure and asked to convert to another measure. For instance, you'll be given some volume in "gallons" and be asked to convert the volume to "fluid ounces". They will have given you (or else you can easily find) the conversion units that are suitable to the task.

Students will multiply and divide a recipe to feed groups of various sizes. Students will use unit rates or proportions and think critically about real world applications of a baking problem.

This Desmos activity in an introductory lesson to unit rate.  The lesson starts by having students make an estimate on performing a "clicking task" and actually performing the task.  Students are asked to reflect on the comparison between their estimation and the actual results.  As students begin to conceptualize strategies their ideas evolve into calculating unit rate.  Students use "click bot" data to find the unit rate to determine the "click bot" winner in the clicker challenge.  This lesson is interactive and allows students to work at their own pace.  

This task focuses on using rate language and developing the context of unit rates.  It also focuses on having students look at multiple strategies for solving ratios and encourages a teacher facilitated discussion of these different strategies.

The principal purpose of the task is to explore a real-world application problem with algebra, working with units and maintaining reasonable levels of accuracy throughout.