Find wrong number in series: 4, 5, 7, 12, 19, 35

Concept: In an additive number series, each term is formed by adding a fixed or systematically changing quantity to the previous term. Here, the quantity added doubles at every step — it is a power of 2 that increases as 20, 21, 22, 23, 24. Finding the wrong number means computing each expected term from this rule and checking it against the value actually given.

Application:

1. 4 + 20 (= 1) = 5 — matches the given second term, 5.

2. 5 + 21 (= 2) = 7 — matches the given third term, 7.

3. 7 + 22 (= 4) = 11 — but the series shows 12 at this position, so 12 does not match the pattern.

4. Continuing from the correct value 11 (not 12): 11 + 23 (= 8) = 19 — matches the given fifth term, 19.

5. 19 + 24 (= 16) = 35 — matches the given sixth (last) term, 35.

Cross-check: Checking consecutive differences confirms this: the differences should double at each step — 1, 2, 4, 8, 16. The actual differences in the given series are 5 − 4 = 1, 7 − 5 = 2, 12 − 7 = 5, 19 − 12 = 7, 35 − 19 = 16. Only the third difference (5) breaks the 1-2-4-8-16 doubling pattern; replacing 12 with 11 restores the clean progression 1, 2, 4, 8, 16 throughout.

Result: So 12 is the wrong number in the series; the correct term at that position would be 11.