Multiplication and Division

Long Division

When you divide a number, you are splitting it equally. In Lesson 3, you learned that division can be a way to understand real-life situations. For example, imagine a car dealership has 15 cars. The manager wants the cars parked in three equal rows.

You could write the situation like this and use a times table to solve it:

After the cars are divided, counting them shows that each row should have five cars. Now, let's say the car dealership has 42 cars and the manager wants to park them in three rows. The situation would look like this:

This problem is harder to solve. It would take a lot of time to divide that many cars into three groups. Plus, there's no 42 in the 3's column on the times table. Fortunately, there is a way to set up the problem that makes it easy to solve one step at a time. It's called long division.

Let's learn how to set up these problems. We'll look at the problem we discussed above: 42 / 3.

In the last lesson, we learned how to write division expressions.
However, dividing a larger number is easier when the expression is written in a different way.
Instead of writing the numbers side by side with a division symbol...
Instead of writing the numbers side by side with a division symbol... we'll use a different symbol called a division bracket.
The number you're dividing goes under the division bracket. That's 42.
To the left of the division bracket, write the number you're dividing by. In our problem, it's 3.
The division bracket is also an equals sign. The quotient, or answer, is written above it.
Let's try setting up another expression, 125 / 25. First, write the division bracket.
Next, write the number being divided, 125.
Finally, write the number we're dividing by, 5.
Remember, you should be careful to set up long division problems correctly.
The number you're dividing goes under the division bracket...
The number you're dividing goes under the division bracket... and the number you're dividing by goes to the left of it.