Think of it this way: Make the 250 25 and the 0.12 to 1.2 to make it easier to multiply. Then, you multiply 25 by 1, and then by 2. You divide the answer you got from 2*25 by 10, to keep the decimal place in place (you get 5). Then, you add the products of 25*1 and 25*0.2, and get 30 in all.
Hope this helps!