Practice Exercises for Number Theory

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Directions: Read each question below. Click once in an ANSWER BOX and type in your answer; then click ENTER. Do not enter commas in your answers. After you click ENTER, a message will appear in the RESULTS BOX to indicate whether your answer is correct or incorrect. To start over, click CLEAR.

1. Find the greatest common factor of 28 and 72.
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2. Find the least common multiple of 15 and 25.
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3. Name one prime number from 80 to 89.
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4. The number 91 is composite. Name a number other than 1 and itself that is a factor of 91.
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5. Which number is divisible by 3?  49, 87, 103, 119
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6. Which number is divisible by 8?  1821, 1496, 1246, 1586, 1634
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7. Write fourteen squared in standard form.
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8. Write nine cubed in standard form.
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9. The numbers 1, 8, 64, 512, ... are each powers of 8. What is the next number in the list? 
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10. If five to the fourth power is 625, then what is five raised to the fifth power?
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Elementary Math Lessons
Factors and GCF
Multiples and LCM
Primes and Composites
Divisibility Rules
Exponents
Patterns and Exponents
Practice Exercises
Challenge Exercises
Solutions

IXL