Number series (next term): Product of digits of the previous term. Given sequence: 66, 36, 18, ? Use the digit-product rule to continue the series. Choose the correct value.

ObservationEach term equals the product of the digits of the previous term.

Step-by-step calculation66 → 6×6 = 3636 → 3×6 = 1818 → 1×8 = 8

Common pitfallsAssuming constant ratio or difference; the rule is digit-wise multiplication.