First you have to find a common demoninator, 1 and 5 both fit into 5. (Put 3 over 1 to make a fraction) Now multiply 1 by 5 because it makes 5. Also multiply 3 by 5 to make 15. now you should have 15 over 5 as a fraction. Now add the two numerators and simplify. Sorry if that sounds confusing!$${\mathtt{3}}{\mathtt{\,\times\,}}{\mathtt{5}} = {\mathtt{15}}$$
$${\mathtt{1}}{\mathtt{\,\times\,}}{\mathtt{5}} = {\mathtt{5}}$$ Now simplify! You can divide 15 and 5 by 5 so$${\frac{{\mathtt{15}}}{{\mathtt{5}}}}$$ = $${\frac{{\mathtt{3}}}{{\mathtt{1}}}}$$ = $${\mathtt{3}}$$ hope that helps!
