What should come in place of the question mark (?) in the following number…

In this type of number series, each term is formed by adding a perfect cube to the previous term, where the base of the cube changes by a fixed step across the series. To find a missing term, first identify how the cube's base is changing from term to term, then verify that pattern against every given term before applying it to the gap.

1. 3 + 123 (= 1728) = 1731

2. 1731 + 103 (= 1000) = 2731 (missing term)

3. 2731 + 83 (= 512) = 3243

4. 3243 + 63 (= 216) = 3459

5. 3459 + 43 (= 64) = 3523

The bases of the cubes added — 12, 10, 8, 6, 4 — decrease by 2 at each step, and applying this rule reproduces every one of the given terms (3243, 3459, 3523) exactly, confirming the pattern.

Hence, the missing term is 2731.