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Maintenance Due Calculator

Run the Maintenance Due Calculator MicroSim Fullscreen

You can include this MicroSim on your website using the following iframe:

<iframe src="https://dmccreary.github.io/robot-arm/sims/maintenance-due-calculator/main.html"
        height="662px" width="100%" scrolling="no"></iframe>

Description

Move three sliders to see when a maintenance task becomes due: the hours of use now, the hours at which the task was last done, and its interval. Then solve six problems about hours left, percent used and weeks until due. Used in Chapter 18.

Explore mode starts with a task that is overdue: 42 hours of use now, last done at 30 hours, with an interval of 10 hours. The bar shows how much of the interval is used, and the state is ok, soon (at 80 percent) or due (at 100 percent). The intervals of the example schedule are examples to start from and not a manufacturer's figures.

Lesson Plan

Grade level: Middle school and up (age 12+). Time: 10 to 15 minutes.

  1. Predict first. Before you move a slider, say what will happen to the hours left. What happens when the task is done again and Last done jumps up to Hours now?
  2. Explore. Find a setting where the state is soon, and one where the hours left are below zero.
  3. Problems. Press Start. Six problems: choose the right formula, type the answer as a number and press Check. You get one try for each problem, and mastery is 5 of 6.
  4. Think about it. Why does the schedule count hours of use and not days on the calendar?

Hours left is the interval minus the hours since the task was last done. It is not the interval minus the hours now, and for an overdue task it goes below zero.

Specification

The learning objective, evidence of mastery and content for this MicroSim are specified in Chapter 18: Projects, Operation, and Teaching.