What is the smallest positive number that must be added to 243 to make it divisible by 9?
- A.9 ✓
- B.8
- C.11
- D.10
Explanation: 243 is already a multiple of 9 (243 = 27 × 9). Since the number added must be positive, the smallest choice is the next multiple: adding 9 gives 252 = 28 × 9.
Class 6 IMO Mathematics Olympiad practice · Number Sense · Factors, Multiples & Primes
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