Example: Use synchronized lists

Updated 28 Aug 2023

The Link ID box in Options tab of the Edit Algorithmic Values window lets you synchronize two or more lists so that there is a one-to-one correspondence between the elements in the list.

In this example, students are asked to state the digit in the nth decimal place of the irrational number pi. Because there is no pattern to the digits, you cannot use a formula to determine the digit. Instead, you create one list for the digits and another list for the place value. You then use the link ID to synchronize the two lists so that the correct digit is selected for the given place value.

The value of pi to 10 decimal places is 3.1415916535. Your first list is each of the digits in the decimal part of pi, entered in order from left to right. The second list is the decimal place names, entered in order from left to right.

  1. Open the Custom Question Builder.
  2. Select Start with an empty template and click Next.
  3. Select the format Full and click Next.
  4. Enter the algorithms defined in the following table:
    NameDefinition

    List of values

    		Link ID
    ~digitdecimal digits for pi 1, 4, 1, 5, 9, 1, 6, 5, 3, 51
    ~placedecimal place valuetenth, hundredth, thousandth, ten-thousandth, hundred-thousandth, 6th decimal, 7th decimal, 8th decimal, 9th decimal, 10th decimal1

    Be sure to enter the lists of values in the exact order specified. Because they are text values, enclose all values of ~place with quotation marks.

    Enter the value 1 in the Link ID column for both algorithmic values. When defining a link ID, you can use any number or letter but the link ID value must match in each list you want to synchronize. When you are done, your Algorithmic Values List looks like this:

  1. In the question and answer area, enter:

    The digit in the place of the irrational number is

    (Use the Equation Editor to insert the pi symbol.)

  2. In this sentence, put your cursor in front of "place," click Algorithmic Values, and choose place from the list. Add a space after the algorithmic value.
  3. Put your cursor at the end of the sentence, enter a space, and click Short Answer to open the Edit Answer Definition window:
    1. On Step 1, select Answer is text or contains a symbol.
    2. On Step 2, click into the row under Value and enter ~digit.
    3. On Step 3, click Next and then click Save on Step 4.

With algorithmic value names displayed, your problem statement and answer prompt look like this:

  1. Click Preview Exercise to see how your question looks for your students. Enter the correct answer and an incorrect answer to check the behavior.
  2. When you are satisfied with your question, dismiss the Preview window and click Save.

See Use a pie chart in a math question for another example of a question that uses link IDs.