The Life Starter
Sign up
Grade 3 · lesson 3 of 4

Check a twenty-second scrub model

Check a twenty-second scrub model

About 18 minutes, plus any extended practice

Download the grade pack

Supplied materials

  • Paper or a text document; all cases below are original fictional learning inputs.
  • An adult may read aloud; drawing or spoken answers are valid. No personal health information or physical performance is required.
  • The separate worked case gives secondsPerSegment=4, segments=6. Multiply segment length by segment count to find modeled scrub time. First identify the quantities and keep their units consistent. The calculation is 4*6=24 seconds. That result answers this supplied planning question only. It does not establish what a real person did, diagnose a condition or prove physical skill. Compare the units with the question before accepting a number.
  • Fictional case 1: secondsPerSegment=5, segments=3. What is the modeled result using the stated method?
  • Fictional case 2: secondsPerSegment=4, segments=5. What is the modeled result using the stated method?
  • Fictional case 3: secondsPerSegment=6, segments=4. What is the modeled result using the stated method?
  • Fictional case 4: secondsPerSegment=3, segments=6. What is the modeled result using the stated method?
  • Fictional case 5: secondsPerSegment=7, segments=3. What is the modeled result using the stated method?
  • Fictional case 6: secondsPerSegment=2, segments=12. What is the modeled result using the stated method?

Learn the idea

Community handwashing includes a scrub of at least twenty seconds. A pretend timer can divide that scrub into equal parts. The arithmetic tells us planned scrub time; it does not test germ removal.

Multiply seconds in each segment by the number of segments. Do not count wetting, rinsing or drying as scrub seconds when the question specifically asks about scrubbing. Those are separate parts of the routine.

Use supplied timers on paper. Do not create contamination tests. If the result is less than twenty seconds, revise the planned scrub. A total meeting the time threshold still needs the other handwashing steps to be a complete routine.

  1. Read or listen to the pretend story. Point to the details the question gives you.
  2. Multiply seconds per scrub segment by the number of segments. Keep wetting, rinsing, and drying out of the scrub total.
  3. Check your answer against the example. Say what matches and what you would change.
  4. Try the practice questions, then the extra task. Drawing or spoken answers are welcome.
Worked example

See the method in action

The separate worked case gives secondsPerSegment=4, segments=6. Multiply segment length by segment count to find modeled scrub time. First identify the quantities and keep their units consistent. The calculation is 4*6=24 seconds. That result answers this supplied planning question only. It does not establish what a real person did, diagnose a condition or prove physical skill. Compare the units with the question before accepting a number.

Your turn

Check your reasoning

Your answer is temporary and is not saved to an account. Download your current answer before leaving or reloading. Written work on paper or in another app stays in your own file.

Helpful tips
  • Multiply equal scrub segments; other routine steps are not scrub time.
  • At least 20 seconds refers to scrub; the full routine still needs wet, lather, rinse and dry.
Check a twenty-second scrub model: Fictional case 1: secondsPerSegment=5, segments=3. What is the modeled result using the stated method?

Feedback appears here after you check. This is practice, not a graded school assessment.

See the answer and explanation

15 seconds

Multiply segment length by segment count to find modeled scrub time. With secondsPerSegment=5, segments=3, calculate 5*3=15 seconds. This is a supplied model, not a personal health assessment.

Take it further

Changed case: secondsPerSegment=5, segments=5. Show the operation. Expected: 5*5=25 seconds. Explain what the unit means and remember that this is a pretend calculation.

Nothing here is saved to an account or sent to a teacher. The answer download includes your current choice and any checked feedback. It does not include choices from the separate More practice section. Download that section separately.

More practice: try new cases

Choose an answer for each problem. Explain your method on paper, then use the feedback to decide what to revisit.

More practice: try new cases
1. Check a twenty-second scrub model: Fictional case 2: secondsPerSegment=4, segments=5. What is the modeled result using the stated method?
Need a hint?
  • Multiply equal scrub segments; other routine steps are not scrub time.
  • At least 20 seconds refers to scrub; the full routine still needs wet, lather, rinse and dry.
2. Check a twenty-second scrub model: Fictional case 3: secondsPerSegment=6, segments=4. What is the modeled result using the stated method?
Need a hint?
  • Multiply equal scrub segments; other routine steps are not scrub time.
  • At least 20 seconds refers to scrub; the full routine still needs wet, lather, rinse and dry.
3. Check a twenty-second scrub model: Fictional case 4: secondsPerSegment=3, segments=6. What is the modeled result using the stated method?
Need a hint?
  • Multiply equal scrub segments; other routine steps are not scrub time.
  • At least 20 seconds refers to scrub; the full routine still needs wet, lather, rinse and dry.

Your choices are temporary. Feedback appears after you check all the answers.

Nothing here is saved to an account or sent to a teacher. Keep your own notes or download them before leaving. The score describes these questions; it does not certify subject mastery.

Check the subject sources

These LifeStarter passages, scenarios and exercises are authored for this Academy with AI assistance and review. External resources keep their publishers’ terms. A grade label suggests a starting level; it does not establish alignment with your school’s complete requirements.