Look at this series: 664, 332, 340, 170, ____, 89, ... What number should fill…

Concept: In an alternating-operation series, two different operations are applied in a strict repeating two-step cycle to consecutive terms. To find the pattern, test each pair of consecutive given terms for a consistent relationship - division, multiplication, addition, or subtraction - and confirm the same two operations repeat in the same order across the whole series.

Application:

1. 664 divided by 2 equals 332

2. 332 plus 8 equals 340

3. 340 divided by 2 equals 170

4. 170 plus 8 equals 178, the missing term

5. 178 divided by 2 equals 89

Cross-check: The computed value 178, when divided by 2, gives 89 - exactly the next term stated in the series - confirming that the alternating divide-by-2/add-8 pattern holds consistently across all six terms.