Factors, primes and multiples
Answers are for parents and teachers.
1
List all the factors of 28 and say if 28 is prime or composite.
1, 2, 4, 7, 14, 28. Composite.
2
List the prime numbers between 30 and 50.
31, 37, 41, 43, 47.
3
Find the GCF of 32 and 48.
Factors of 32: 1, 2, 4, 8, 16, 32. Factors of 48: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48. GCF = 16.
4
Farida has 30 red flowers and 45 white flowers. She makes identical bunches with none left. How many bunches at most, and what is in each?
GCF of 30 and 45 is 15. 15 bunches, each with 2 red and 3 white flowers.
5
Two buses leave a station at 8:00 a.m. One leaves every 12 minutes and the other every 18 minutes. When do they leave together again?
LCM of 12 and 18 is 36. They leave together at 8:36 a.m.