Divisibility - practice problems

Divisibility concerns whether one integer can be divided by another with no remainder, written as a|b (a divides b) when b/a is an integer. Divisibility rules provide shortcuts: a number is divisible by 2 if even, by 3 if digit sum is divisible by 3, by 5 if ending in 0 or 5, by 9 if digit sum is divisible by 9, and so on. Understanding divisibility is essential for factoring, finding greatest common divisors (GCD), least common multiples (LCM), and simplifying fractions. Divisibility properties include transitivity and compatibility with arithmetic operations. These concepts underpin number theory, modular arithmetic, and have applications in scheduling, patterns, and cryptography. Testing divisibility helps identify factors and prime numbers efficiently.

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