Practice for lesson 4 of 15, 9 problems
Practice: Divisibility rules, prime numbers and prime factorization
Divisibility and prime number practice problems with solutions: divisibility rules, listing factors, prime or composite, prime factorization and puzzles with missing digits.
Review the lessonWork each problem out on paper before you open the solution. If your answer is off, compare the steps and find where you went wrong. If a problem stops you cold, go back to the lesson: every set links to it.
Warm-up
Level up
Word problems
Quick check
Practice 8Quick check
Which number is prime?
\(39 = 3 \cdot 13\), \(49 = 7 \cdot 7\), \(57 = 3 \cdot 19\).
Practice 9Quick check
What is the prime factorization of \(90\)?
\(90 = 2 \cdot 3 \cdot 3 \cdot 5\). The first and third choices still contain composite factors; the last one equals \(60\).
All done?
If you got most of them right, you're ready to move on. If not, reread the lesson and try the ones you missed again in a few days.