A89: another BASIC question

i don't know if you can do this with a list or matrix, but i'm going to try.

i have a list, or matrix with the numbers 5,10,15,20,25,30 (example)

suppose i do a whole bunch of stuff and i get the number 10. how do i scan the matrix or list to see if that number, 10, is in it?

i've stored it into a {5,10,15,20,25,30}->list1

then i did

list1=10

at the home screen and it said

false

which doesn't seem right.

also, could you please say if i can do this with both or just one. (matrix/list)
{-kimo-}