Slide 1 / 192 Slide 2 / 192 5th Grade Decimal Concepts 2015-11-16 www.njctl.org Slide 3 / 192 Table of Contents Click on a topic to go to that section. What is a Decimal? Identify Place Values Read and Write Decimals Compare & Order Decimals Round Numbers to Designated Place Values Glossary & Standards
Slide 4 / 192 What is a Decimal? Return to Table of Contents Slide 5 / 192 Decimals What is a decimal number ? A Decimal Number ( based on the number 10, tenth parts, and powers of ten ) contains a Decimal Point. Click to find out! Where do we see decimals being used? Slide 6 / 192 Click on the photo to find out! In baseball, batting In races to show speed. averages are in decimals. Miguel The women's record for the Cabrera has a fastest 100 meter dash is batting average of 10.88 seconds. 0.387 Music Stations With money to that show their show dollars radio frequency and change. in decimals. This shows $6.91. And many other places!
Slide 7 / 192 Why do we need decimals? Decimals are used in situations when more precision is needed. For instance, when two people cross the finish line, someone will win by a fraction of a second. We show those fractions as decimals. If you are spending money, many things are not worth an exact dollar amount. Slide 8 / 192 Decimals on a Number Line Lets take a look at decimals on a number line. Teacher Notes Click on the picture below for an interactive number line. Slide 9 / 192 Identify Place Values Return to Table of Contents
Slide 10 / 192 Place Value Chart Our place value chart is almost like a mirror image, with a line between the ones place and the decimal point. . tens ones thousands hundreds tenths hundredths thousandths Everything to the left ends in "s" and everything to the right ends in "ths" Slide 11 / 192 Place Value Chart Slide 12 / 192 1 What digit is in the thousandths place? 987,654.0123 A 7 B 2 C 3 D 8
Slide 13 / 192 2 What digit is in the tenths place? 987,654.0123 A 1 B 4 C 0 D 5 Slide 14 / 192 3 What digit is in the hundredths place? 987,654.0123 A 5 B 0 C 1 D 2 Slide 15 / 192 Tenths Yellow Rod How many yellow rods are needed to fill the blue block? 10 click What is the value of a yellow rod? one-tenth (0.1) click Blue Block One Unit (1)
Slide 16 / 192 Money and Decimals Think of it in terms of money. How many dimes does it take to make a dollar? _________ dimes = 1 dollar So, a dime is one tenth of a whole dollar. Slide 17 / 192 Hundredths Yellow Rod Red Block How many red blocks are needed to fill the blue block? 100 click (Hint: Fill a yellow rod with red blocks) What is the value of a red block? one-hundredth (0.01) click Blue Block One Unit (1) Slide 18 / 192 Money and Decimals Think of it in terms of money. How many pennies does it take to make a dollar? _________ pennies = 1 dollar So, a penny is one hundredth of a whole dollar.
Slide 19 / 192 Money and Decimals So a dollar is a whole. A dime is a tenth. And a penny is a hundredth. . one tenth hundredth What if we had a coin that was smaller than a penny? How many times smaller than a penny do you think it would be? What would you call it? Slide 20 / 192 Representing Units 3 yellow rods = 0.3 three tenths Blue = One Unit Slide 21 / 192 Representing Units 23 red blocks = 0.23 twenty three hundredths Blue = One Unit
Slide 22 / 192 Interactive Number Grid - Use to Show Decimals Click to Go to Interactive Site Slide 23 / 192 4 If the square equals one whole, what does the shaded area represent? Slide 24 / 192 5 If the square equals one whole, what does the shaded area represent?
Slide 25 / 192 6 If the square equals one whole, what does the shaded area represent? Slide 26 / 192 7 If the square equals one whole, what does the shaded area represent? Slide 27 / 192 8 If the square equals one whole, what does the shaded area represent?
Slide 28 / 192 Money and Decimals Lets look at place value using money again. . ones tens thousands hundreds tenth hundredth dime penny ______ pennies = 1 dime ______ dimes = 1 dollar bill ______ 1 dollar bills = 1 ten dollar bill ______ ten dollar bills = 1 hundred dollar bill What do you notice about place value? Slide 29 / 192 Place Value As you look at the place value chart, how many times does the value of the number decrease as you go to the right? Each place has a value that is one tenth of the value of its place to its left. Click to reveal Slide 30 / 192 Representing Units Lets take a closer look at what happens as we move to the left on the place value chart. Teacher Notes 10 tens = 1 hundred 10 ones = ten one x 10 = ten x 10 = 1 hundred x 10 = 1 thousand...
Slide 31 / 192 Money and Decimals Lets look at place value using money again. . tens ones thousands hundreds tenth hundredth penny dime A hundred dollars is ____ times as much as ten dollars A ten dollars is ____ times as much as a dollar A dollar is ____ times as much as a dime A dime is ____ times as much as a penny What do you notice about place value? Slide 32 / 192 Place Value As you look at the place value chart, how many times does the value of the number increase as you go to the left? Each place has a value that is 10 times the value of its place to the right. Click to reveal Slide 33 / 192 Representing Units Lets take a closer look at what happens as we move to the right on the place value chart. 1 hundred 10 = ten ten 10 = one 1 thousand 10 = 1 hundred 10 = ten 10 = 1
Slide 34 / 192 Place Value . Lets use place value to compare decimal #s. tenths hundredths 33 . standard form word form thirty-three hundredths 0.3 + 0.03 expanded form The 3 in the tenths place is ten times as much as the 3 in the hundredths place. Slide 35 / 192 Place Value . tenths hundredths 44 . standard form forty-four hundredths word form expanded form 0.4 + 0.04 The 4 in the hundredths place is one tenth the 4 in the tenths place. Slide 36 / 192 9 In the number 3.33, the digit in the tenths place is one tenth of the digit in the hundredths place. True False
Slide 37 / 192 10 In the number 11.111, the digit in the thousandths place is one tenth of the digit in the ________ place. A ones B tenths C hundredths Slide 38 / 192 11 A digit in the ones place is 100 times as much as a digit in the ______ place. A ones B tenths C hundredths Slide 39 / 192 12 The value of the 6 in 26.495 is _______________ the value of the 6 in 17.64. A 1/10 B 10 times C 1/100 D 100 times From PARCC EOY sample test #18
Slide 40 / 192 13 The value of the 3 in 0.931 is _______________ the value of the 3 in 0.384 A 1/10 B 10 times C 1/100 D 100 times From PARCC EOY sample test #18 Slide 41 / 192 Decimals on the Number Line 3 2 What does each line, between the whole numbers 2 and 3, represent on this number line ? Label the number line. Slide 42 / 192 Decimals on the Number Line 33 32 What does each line, between the whole numbers 32 and 33, represent on this number line ? Label the number line.
Slide 43 / 192 Decimals on the Number Line 4.4 4.3 What does each line, between the decimal numbers 4.3 and 4.4, represent on this number line ? Label the number line. Slide 44 / 192 Decimals on the Number Line 0.63 0.64 What does each line, between the decimal numbers 0.63 and 0.64, represent on this number line? Label the number line. Slide 45 / 192 National Library of Virtual Manipulatives Click to go to web site. Change Places to "Decimals" at the bottom left. Zoom in to drag the dot more precisely.
Slide 46 / 192 14 Which letter corresponds to the number 4.4 on this number line? A B C D 0 10 Slide 47 / 192 15 Which letter corresponds to the number 6.8 on this number line? 0 A B C D 10 Slide 48 / 192 16 Which letter corresponds to the number 0.8 on this number line? 0 A B C D 1
Slide 49 / 192 17 Which letter corresponds to the number 7.2 on this number line? A B C D 7 8 Slide 50 / 192 18 Which letter corresponds to the number 19.3 on this number line? 19 A B C D 20 Slide 51 / 192 19 Which letter corresponds to the number 324.5 on this number line? A B C D 4 325 2 3
Slide 52 / 192 20 Which letter corresponds to the number 5.35 on this number line? 5.3 5.4 A B C D Slide 53 / 192 21 Which letter corresponds to the number 1.08 on this number line? 1 B C 1.1 A Not plotted on this number line D Slide 54 / 192 22 Which letter corresponds to the number 6.23 on this number line? 6.2 6.3 A B C D Not plotted on this number line
Slide 55 / 192 23 Which letter corresponds to the number 17.4 on this number line? 17.1 17.2 A B C Not plotted on this number line D Slide 56 / 192 Read & Write Decimals Return to Table of Contents Slide 57 / 192 In this unit, we will be working with numbers written in standard, word, and expanded form. Lets review each.
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