jaotuvusreegleid

Divisibility rules are shortcuts for determining whether a number can be evenly divided by another number without performing long division. These rules are particularly useful for mental calculations and in number theory.

A number is divisible by 2 if its last digit is even (0, 2, 4, 6, or 8). For example, 124 is divisible by 2 because its last digit is 4.

A number is divisible by 3 if the sum of its digits is divisible by 3. For instance, 369 is divisible by 3 because 3 + 6 + 9 = 18, and 18 is divisible by 3.

A number is divisible by 4 if the number formed by its last two digits is divisible by 4. For example, 1324 is divisible by 4 because 24 is divisible by 4.

A number is divisible by 5 if its last digit is either 0 or 5. The number 750 is divisible by 5 because its last digit is 0.

A number is divisible by 6 if it is divisible by both 2 and 3. So, 432 is divisible by 6 because it is even and the sum of its digits (4+3+2=9) is divisible by 3.

A number is divisible by 9 if the sum of its digits is divisible by 9. For instance, 810 is divisible by 9 because 8 + 1 + 0 = 9, which is divisible by 9.

A number is divisible by 10 if its last digit is 0. The number 120 is divisible by 10.

Divisibility rules can be extended to other numbers, though they may become more complex. These fundamental rules are a cornerstone of arithmetic and provide efficient ways to analyze the properties of integers.