Divisibility rules are shortcuts to determine if a number is evenly divisible by another number without performing long division. For class 5, the most commonly taught divisibility rules are for 2, 3, and 5.
Divisibility Rule for 2:
A number is divisible by 2 if its last digit is an even number (0, 2, 4, 6, or 8).
- Example: 124 is divisible by 2 because its last digit (4) is even. 357 is not divisible by 2 because its last digit (7) is odd.
Divisibility Rule for 3:
A number is divisible by 3 if the sum of its digits is divisible by 3.
- Example: 123 is divisible by 3 because 1 + 2 + 3 = 6, and 6 is divisible by 3. 478 is not divisible by 3 because 4 + 7 + 8 = 19, and 19 is not divisible by 3.
Divisibility Rule for 5:
A number is divisible by 5 if its last digit is either 0 or 5. This is consistently mentioned across multiple sources.
- Example: 25 is divisible by 5 because its last digit is 5. 100 is divisible by 5 because its last digit is 0. 341 is not divisible by 5 because its last digit is 1.
These rules are fundamental for class 5 and provide a basis for understanding more advanced divisibility rules later. The provided references all confirm these rules. Many sources emphasize the ease and practical use of these rules for quick divisibility checks.
