Significant Figures

Numerical questions displaying this icon WebAssign will check your answer for the correct number of significant figures require your students to answer with the correct value specified to the correct number of significant digits. If needed, you can turn off significant figure checking, change the tolerance at the last significant digit, or give partial credit if the student's answer is given with too many significant digits.

How-ToInstructor HelpWebAssign

WebAssign uses the following rules to calculate the correct number of significant digits. If you teach using different rules, consider turning off significant figure checking.

Operation

Rule

Examples

Addition

Use the fewest number of decimal places specified in any of the operands.

2.46 + 6.1743 = 8.63

Subtraction

Use the fewest number of decimal places specified in any of the operands.

3.1415 - 2.2 = 0.9

Multiplication

Use the fewest number of significant figures specified in any of the operands.

1530 × 4.0 = 6100 1530 × 4 = 6000

Division

Use the fewest number of significant figures specified in any of the operands.

444 ÷ 4 = 100 444 ÷ 111 = 4.00

Exponentiation

Use the same number of significant figures as the base.

210 = 1e3 2.00010 = 1024

Logarithms

Use the same number of decimal places in the result as the number of significant figures in the number you are taking the logarithm of.

log10(27) = 1.43 ln(0.026) = -3.65

Antilogarithms

Use the same number of significant figures in the result as the number of decimal places in the number you are taking the antilogarithm of.

103.43 = 2700 e-3.65 = 0.026

Set Significant Figure Checking for an Assignment

Assignment settings for significant figure checking override the class settings.

  1. In the Assignment Editor, expand Settings Scoring Advanced Settings.

  2. Select or clear Mark answers wrong for significant figure errors.

  3. If significant figure checking is enabled, change the tolerance at the last digit.

    Set Answers are correct if last significant digit is within ±.

    For example, if you set Answers are correct if last significant digit is within ± to 2:

    Answer Key

    Answers counted as correct

    4100

    3900, 4.0e3, 4100, 4200, 4300

    12.28

    12.26, 12.27, 12.28, 12.29, 12.30

    0.04

    0.04

  4. If significant figure checking is enabled, give partial credit for answers specified with too many significant digits.

    No credit is awarded for responses that specify too few significant digits.

    1. Select Award credit if answer is correct but has too many significant figure errors.

    2. Set the partial credit percentage to award.

    For example, if you enabled 50% partial credit and the answer key is 40, a student who submitted 41.2 would receive 0.5 points for a 1-point question.

  5. Save customized settings as a template to reuse on other assignments.

    1. Under Settings, click Save as New Template.

      This is only shown if you have changed settings from the default.

    2. Enter your template name.

    3. Click Save Template.

  6. Click Save at the top of the assignment.

Set Significant Figure Checking for class section

Assignment settings for significant figure checking override the class settings.

  1. Open the Class Settings page.

    From My Classes, click Edit Class Settings.

  2. In the Class Settings page, click Advanced Options.

  3. Select or clear Mark answer wrong for significant figure errors.

  4. Select or clear Show SigFigs icon.

  5. Select or clear Icon link to SigFigs help page.

  6. For Tolerance, type an integer between 0 and 9 by which the student's response can differ from the answer key at the last significant digit and still be considered correct.

  7. For Partial Credit, type a number between 0 and 100 to specify the percentage of the question's point value to award for numerically correct responses that are specified with too many significant figures.

    No credit is awarded for responses that specify too few significant figures.

  8. Click Save.