When multiplying by 10's, 100's, 1,000's just move the decimal. Example: 0.49 x 10..... there is one zero in the number 10 so you would move your decimal one space to the right making it 4.9 If you are multiplying by 100 you would move the decimal over two times. Say we're working with 0.49 by moving the decimal typo the right the same amount of zeros we now have 49. The same goes with 1,000. They're are three zeros so you would move took the right the times making 0.49 into 490. There is a zero at the end making it 490 because we have to add something in that digit to show all the place settings. Hope that helps.