How to describe this in a formula?

Dec 2018
42
2
Amsterdam
I want to put the following in a formula, how can I do that?
Set A has numbers ranging from 1 till 10.
The numbers in Set B depend on the number at Set A multiplied by 3.
(So if A=1 then B=3)
(if A=5 then B=15)
(if A=10 then B=30)
 

skeeter

Math Team
Jul 2011
3,130
1,697
Texas
B=3A |A∈{1,2,3,...,9,10}
 

skipjack

Forum Staff
Dec 2006
21,184
2,332
Does "numbers ranging from 1 to 10" mean "the 10 integers from 1 to 10"?