Place Value: Standard Form

Lesson Plan - Get It!

Audio:

Place value describes the value of each digit in a number.

Without place value, it would be difficult to determine the value of money, how fast a car is traveling, or how hot an oven is. Without place value, numbers are just numbers.

It is important that you are able to identify the ones place through the millions place with whole numbers, and the tenths place through the thousandths place with decimal numbers.

Look at the chart below. If you have not already identified the value of the underlined number at the beginning of the lesson, use this chart to help you:

Did you say the value of the underlined number is five ten-thousands? You could also say the value is 50,000. Use the chart to discuss the following questions with your teacher or parent:

• What do you notice about all the numbers behind the decimal?
• What do you notice about the numbers in front of the decimal?
• What is used to separate whole numbers and decimal numbers?

You should have noticed that the numbers behind the decimal all end in –th. You know you are reading or saying a decimal number when it ends in –th. You also should have noticed that the whole numbers are arranged into groups of three. Each of these groups is referred to as a period. Periods are separated with a comma. Whole numbers and decimal numbers are separated with a decimal.

There are three ways to write and say a number: standard form, written form, and expanded form.

In this lesson, you will learn to read, write, and compare numbers written in standard form. Look at the examples below. Each example represents the same number. Tell your teacher or parent which number you think is written in standard form and explain your answer:

• 5,623.07
• five thousand, six hundred twenty-three and seven hundredths
• 5,000 + 600 + 20 + 3 + 0.07

If you said the first example is written in standard form, you are correct! The second example is written in written form, and the third example is written in expanded form.

Standard form is how you will most often see numbers written. When writing and reading numbers in standard form, remember:

• Whole numbers are divided into groups of three. Each grouping should be separated with a comma. When reading a number written in standard form, pause briefly when reading the comma.
• The decimal should be read as "and." Therefore, it is important not to say "and" at any other point when reading the number. For example, do NOT say, "Six hundred and twenty-three," because this would indicate there is a decimal between these numbers.

When you are ready, move on to the Got It? section to practice reading and writing numbers in standard form.