Divisibility means when a number can be divided by another number without leaving any extra pieces or a remainder.
Think of it like sharing candy with your friends. If you have 12 pieces of candy and you want to share it equally among 4 friends, each friend would get 3 pieces of candy. That means 12 is divisible by 4 because it can be divided into 4 equal parts.
We use divisibility rules to quickly figure out if a number is divisible by another number. For example, if a number ends in 0 or 5, it is divisible by 5. If the sum of its digits is divisible by 3, then the number is also divisible by 3. Can you think of another example?