When dividends and divisors are multiples of 10, breaking apart the divisor and dividing by 10 makes the division problem simpler. Te same is true when you can break apart a divisor and divide by 100 or by 1000, because when you divide by 100, you just move all digits two places to the right, and when you divide by 1000 ,you just move all digits three places to the right, thus making your quotient 1000 times smaller than the dividend.