If 8 is and element of a intersection b then 8 is and element of a and 8 is an element of b

Just for example's sake:

A = {1, 2 a, car, 8, 100,...}
B= { jet, trouser, 8, 2100}

Then A and B = A∩B meaning ONLY the element that belong to A AND B, that is 8. 
To better understand it, draw a Venn diagram