**Part B: Expanded Form**

In the last lesson, we learned the fundamentals of number place values. Now we are going to look at expanded form. In expanded form, we are writing a number it terms of a sum of its parts. Expanded form gives us the basis for addition and subtraction which we’ll review in the next lesson. To put in expanded form, all we first need to know the place values. Which we just reviewed. Now we will use the place values and expand a number.

Let’s do an example:

We must be sure to keep all of the place values lined up, otherwise, this will not make sense or we’ll get the wrong answer (see Fig. 1).

If we expand each place value and then add all of these numbers up we are basically separating and recombining each digit to get our final answer in the standard form. We call our answer, **4382, **the standard form because this is normal way we would write values and numbers.

Why do you think the expanded form so important? Expanded form is important because it is how our minds add numbers. We don’t talk about this or even think about this process when we are adding, but this is in fact what we are doing. All addition is the expanding and contracting of numbers to get them in standard form.

**Expanded Form Exercise**

Next, we will look at addition and subtraction in lesson 2.