Virtual Labs

1. Which of the following numbers is divisible by 9?

a: 12345 Explanation

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b: 9009 Explanation

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c: 12101 Explanation

Explanation

d: 10001 Explanation

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2. What is the digital root of 9876?

a: 3 Explanation

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b: 9 Explanation

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c: 6 Explanation

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d: 1 Explanation

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3. Which of the following is a property of circular numbers?

a: Multiplying by the units digit rotates the number's digits right Explanation

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b: They are always prime Explanation

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c: They are always even Explanation

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d: They are always less than 1000 Explanation

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4. Which of the following numbers has a digital root of 9?

a: 123456 Explanation

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b: 9009 Explanation

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c: 12101 Explanation

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d: 10001 Explanation

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5. What is the main use of the digital root in divisibility tests?

a: To check if a number is prime Explanation

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b: To check if a number is divisible by 9 Explanation

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c: To find the largest digit Explanation

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d: To check if a number is even Explanation

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6. Which of the following is NOT a property of circular numbers?

a: They always end with 0 Explanation

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b: Multiplying by the units digit rotates the digits Explanation

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c: They can be multi-digit numbers Explanation

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d: They are rare Explanation

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7. Which of the following numbers is circular when multiplied by its units digit?

a: 12345 Explanation

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b: 102564 Explanation

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c: 9009 Explanation

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d: 12101 Explanation

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8. What is the digital root of 123456?

a: 3 Explanation

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b: 9 Explanation

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c: 6 Explanation

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d: 1 Explanation

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9. Which of the following statements about divisibility by 9 is true?

a: A number is divisible by 9 if the sum of its digits is divisible by 9 Explanation

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b: A number is divisible by 9 if it ends with 9 Explanation

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c: A number is divisible by 9 if it is even Explanation

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d: A number is divisible by 9 if it is prime Explanation

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10. Which of the following is NOT a use of digital roots?

a: Checking divisibility by 9 Explanation

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b: Finding circular numbers Explanation

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c: Number puzzles Explanation

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d: Quick mental math Explanation

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