Divisibile Rule

Math Facts: 11

Math Facts

Divisibile Rule : Numbers are divisible by 9 if the sum of all the individual digits is evenly divisible by 9.

Divisibile Rule:

Yes, that’s correct. A number is divisible by 9 if the sum of its digits is divisible by 9. This is a handy rule in mathematics, known as the “divisibility rule for 9.” Here’s a step-by-step explanation:

1. Take any number: For example, let’s consider the number 729.
2. Sum the digits: Add all the individual digits of the number. For 729: (7 + 2 + 9 = 18).

3. Check the sum: Determine if the resulting sum (18 in this case) is divisible by 9.  (18 divided by 9 equals 2, which is a whole number.)

4. Conclusion: Since the sum (18) is divisible by 9, the original number (729) is also divisible by 9.

This rule can be applied to any number. For example:

                                                                                     Number: 234

                                                                             Sum of digits: (2 + 3 + 4 = 9)

                                                                                                     9 is divisible by 9, so 234 is divisible by 9.

                                                                                     Number: 12345

                                                                             Sum of digits: (1 + 2 + 3 + 4 + 5 = 15)

                                                                                                    15 is not divisible by 9, so 12345 is not divisible by 9.

This rule works because of the properties of numbers in base 10 and modular arithmetic. When you add the digits of a number, you’re essentially performing a modulo operation, which helps determine divisibility by 9.

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