Calculations from students' answers

Use it in measurement tasks and practicals where every student works with their own numbers. They record what they measured, and the worksheet shows what follows from it. Each student sees the result for their own data, and it updates the moment they change a value.

Only numeric answers can feed a calculation: a Question with its Answer format set to Numeric, or a Math question.

First make the answers available as variables:

1. Add a Question for each measurement and set its Answer format to Numeric.

2. Open the … menu on the question and choose Publish as variable.

3. Give the variable a clear Display name, such as Distance or Time, and click Save. This is the name you pick in the formula.

Then add the calculation:

1. Click the pencil on a Text item, for example one that reads Speed:, and place the cursor where the result should appear.

2. In the text toolbar, click + (Insert) and choose Insert computed value.

3. Build the formula. To divide distance by time, type / to start a fraction, click Variables and choose Distance for the top, move to the bottom with the down arrow key, and choose Time from Variables again. Numbers and other operators can be typed directly.

4. Under Display mode, choose Value to show only the result, or Expanded to show the formula next to it.

5. If you like, tick Show on its own line (block), fill in Unit (optional), for example m/s, and set Significant figures or Decimals under Format options.

6. Click Add, then click the tick to finish editing the text.

Until the answers it needs are filled in, the calculation shows Waiting for input. As soon as students enter their numbers, the result appears, and it changes straight away if they correct a value, even before they submit. Pointing at a result that uses an answer they have not submitted yet shows Uses an unsubmitted answer. Clicking the result shows it enlarged.

The calculation is shown to students, but it is not an answer and is not marked. What is saved are the numbers they entered: open Results on each measurement question to see what every student submitted. The result is always worked out from those numbers, so they are all you need to check it.

• Publish and name the variables before you write the formula. Variables lists only what has been published, and a name that includes the unit, such as Time (s), makes the right one easy to pick.

• A variable can be used anywhere in the same lecture, and across all its worksheets in a presentation, so the measurement and the calculation do not have to be on the same worksheet.

• The unit is only a label next to the result. Nothing is converted, so ask for the measurements in units that suit the formula, such as metres and seconds for m/s.