Find the next number: 100, 90, 81, 73, ?
- A.64
- B.65
- C.66 ✓
- D.67
Explanation: The differences are −10, −9, −8 — decreasing by 1 each time. Next difference is −7, so 73 − 7 = 66.
Class 6 IMO Mathematics Olympiad practice · Patterns & Sequences · Number & Letter Sequences
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