Answer:
1, 3, 7, 21
Step-by-step explanation:
factors are things you can multiply to get the number.
start with 1 times the number (21)
and then see if 2 can be multiplied by anything to get the number (it can't)
repeat the step with number 3 (it can)
keep repeating the step until you reach a number that has already been listed.
it will never go above the given number
have a wonderful day luv <3
