Foundation
USE WHEN
Population, users, customers, production or membership changes year by year.
BEST METHOD
Reverse Multiplier Method
TARGET
60–90 sec
MASTERY
not started
Population, users, customers, production or membership changes year by year.
Repeated population changes are compound percentage changes.
Work with multipliers; only calculate the actual population at the end if needed.
If final population is given, divide by the compounded growth factor.
Timed drill
Identify the base or invariant before you calculate.
Attempt first · Standard Example
Attempt first · CAT-Level Example
3-level practice ladder
Foundation
CAT Standard
Advanced / Hybrid
cat 2023 slot 3: population falls by y% and then rises by x%, subject to a final-population constraint.