Estimation makes dividing greater (larger) numbers easy. Without estimation problems, it takes us longer to solve long division problems. Sometimes, estimation can give us the wrong answer. We shouldn't worry. It's also very easy to fix that kind of problem.
Take a look at this example:
We round off 53 to 50 and then simplify the problem. Solve 20 divided by 5 (20 ÷ 5). The answer equals 4, so we write 4 on top of the number 4 in the hundreds place. When we multiply 4 times 53, we get 212 (4 x 53 = 212). But 212 is greater than 204. We can't subtract.
What we can do is to make the quotient, or answer, a lesser (smaller) number. Instead of 4, write down 3. Multiply 53 times 3. We get 159 (53 x 3 = 159). This time, we can subtract 159 from 204, and we get 45 (204 - 159 = 45). We have a remainder of 45.
Take a look at this other example:
We round off 39 to 40. Solve 23 divided by 4 (23 ÷ 4). The answer is 5, so we write that above the 5 in the original problem. We multiply 5 times 39. We get 195 (5 x 39 = 195). If we subtract 195 from 235 (235 - 195 = 40), the answer is greater than 39.
What do we do? We make the quotient a greater number. We change the answer to 6. Multiply 39 times 6. We get 234 (39 x 6 = 234). Subtract 234 from 235 (235 - 234). We get a remainder of 1.
Remember, if the remainder is greater than the divisor, we make the quotient greater. If we can't subtract, we give a lesser number for the quotient.
