Answer: 42 = 2 × 21. 2 is prime, so circle it and leave it alone. However, 21 is divisible by numbers other than 1 and itself, so divide it by its smallest prime factor, 3:
21 = 3 × 7. 3 and 7 are both prime, so we are done. ...
42 = 2 × 3 × 7. This is the prime factorization of 42.
Step-by-step explanation: explained above