Calculate a remaining amount after half-lives
Apply an exponential model while distinguishing an expected amount from a tiny-sample guarantee.
Open lesson 1Exponential decay, uncertainty, and model inference
Apply half-life models, interpret probabilistic counts, and infer a rate from bounded evidence.
Before you begin
- Use exponents and fractions; distinguish amount, expectation, and exact individual counts.
Choose by skill rather than age alone. Read with an adult when useful, revisit a lesson, or explore another grade.
Follow the lesson sequence
Calculate a Remaining Fraction
Separate fractional decay from a fixed subtraction.
Open lesson 2Explain Tiny-Sample Decay Variation
Distinguish an expected surviving count from a guaranteed integer count.
Open lesson 3Infer a Half-life and Check a Claim
Use ratios and intervals to assess an exponential-model explanation.
Open lesson 4Review and transfer
After the lessons, try 4 new review cases and a practical task. Each answer has an explanation and a link back to the related lesson.
Open the unit reviewGuest answers are temporary. Keep your own paper or document; this unit does not certify completion or record a school grade.