Transcript Document
Decimal Dan By: Nicole Bueno Oh, hello! I’m so glad you came by! My name is Decimal Dan and I have been waiting to talk to you! I have a very important job around here, but I can’t do it all by myself. Let me tell you what I do. I’m called a decimal point. You know all about whole numbers, right? That’s right! Whole numbers are numbers like 1, 2, 17, 46 and even 156,021! Well, I’m used when we need a way to write a number less than 1. That means a decimal is a smaller part of the number 1. Check this out! 178 649 Whole Numbers Decimal Numbers Look how I come in between the whole numbers and the decimal numbers. That’s my job! Let’s talk about how many parts of one these numbers are showing. 178.649 The first digit is in the tenths place. That means there are six tenths in this number. It would look like this many parts of the number 1: 178.649 This next digit is in the hundredths place. That means there are 4 hundredths in this number. It would look like this many parts of the number 1: 178.649 Finally, this digit is in the thousandths place. That means there are 9 thousandths in this number, and 9 thousandths of the number 1. That’s a lot of little parts! 178.649 Gosh! Put that all together and we have all these parts! That’s: 6 tenths, 4 hundredths, and 9 thousandths. Now that I’ve told you what a decimal point does, maybe you can help my friend, Decimal Dot. Let’s show her where to go to make certain decimal numbers. 345 Where does Decimal Dot go to make this number have 3 tenths? Right! That’s exactly where we place a decimal point to show 3 tenths. 8 3 4 5 Now I need to show 4 tenths. Perfect! I know that there are 4 tenths in this number because of where Decimal Dot is. The first number after the decimal point is the tenths place. 2 0 0 7 Ok, here’s a new one. How does Decimal Dot show that this number has 7 hundredths? You got it. Decimal Dot is right where she needs to be to show 7 hundredths. 2 0 0 7 Hey, you’re pretty good! Now let’s get this number to have 7 thousandths. Where should Decimal Dot go? Exactly! I can now see that there are 7 thousandths in this number. Well it looks like you know exactly where to put us! But no matter where we are, you have to know what the numbers are saying, too. Let’s take a look at some more decimal numbers. .21 and .09 This time Decimal Dot knows where to go, but can you tell her which number is larger? That’s right! There are 2 tenths in the first number and zero tenths in the second number, so .21 is the larger number. .354 .354and and .358 Which one is larger here? Well, there are 3 tenths in both numbers. I can also see that there are 5 hundredths in both numbers. The last digits are different. Which number is larger? 4 thousandths or 8 thousandths? Oh! I get it! So that means .358 is the larger number! You see, Decimal Dot and I have a pretty big job around here. The decimal point shows how many parts of one there are by getting in between whole and decimal numbers. But let me tell you a secret… We can’t do it by ourselves! It’s up to you to know how to use decimal points! Talk to you later! TEKS (4.1) Number, operation, and quantitative reasoning. The student uses place value to represent whole numbers and decimals.The student is expected to: (A) use place value to read, write, compare, and order whole numbers through 999,999,999; and (B) use place value to read, write, compare, and order decimals involving tenths and hundredths, including money, using concrete objects and pictorial models. (4.2) Number, operation, and quantitative reasoning. The student describes and compares fractional parts of whole objects or sets of objects.The student is expected to: (D) relate decimals to fractions that name tenths and hundredths using concrete objects and pictorial models.