Mixed Number Rounding to the Nearest Whole Jen Kershaw Say Thanks to the Authors Click http://www.ck12.org/saythanks (No sign in required) To access a customizable version of this book, as well as other interactive content, visit www.ck12.org CK-12 Foundation is a non-profit organization with a mission to reduce the cost of textbook materials for the K-12 market both in the U.S. and worldwide. Using an open-content, web-based collaborative model termed the FlexBook®, CK-12 intends to pioneer the generation and distribution of high-quality educational content that will serve both as core text as well as provide an adaptive environment for learning, powered through the FlexBook Platform®. Copyright © 2014 CK-12 Foundation, www.ck12.org The names “CK-12” and “CK12” and associated logos and the terms “FlexBook®” and “FlexBook Platform®” (collectively “CK-12 Marks”) are trademarks and service marks of CK-12 Foundation and are protected by federal, state, and international laws. Any form of reproduction of this book in any format or medium, in whole or in sections must include the referral attribution link http://www.ck12.org/saythanks (placed in a visible location) in addition to the following terms. Except as otherwise noted, all CK-12 Content (including CK-12 Curriculum Material) is made available to Users in accordance with the Creative Commons Attribution-Non-Commercial 3.0 Unported (CC BY-NC 3.0) License (http://creativecommons.org/ licenses/by-nc/3.0/), as amended and updated by Creative Commons from time to time (the “CC License”), which is incorporated herein by this reference. Complete terms can be found at http://www.ck12.org/terms. Printed: November 19, 2014 AUTHOR Jen Kershaw www.ck12.org C HAPTER Chapter 1. Mixed Number Rounding to the Nearest Whole 1 Mixed Number Rounding to the Nearest Whole Here you’ll learn to round mixed numbers to the nearest whole number. Remember when you thought about measurement and fractions in the Fraction Rounding to the Nearest Half Concept? Well, Travis is actually going to work on a construction site. Travis is hoping to work with his Uncle Larry for the summer. Uncle Larry is a contractor who works on building houses. Travis has always loved working with his hands and construction seems to be a perfect fit for him. He also loves seeing a house start from nothing and be built. Travis’ Uncle Larry is a bit concerned because Travis is a little young to be working on a construction site, but Travis is sure that he is up to the task. To test things out first, Uncle Larry has asked Travis to come and work with him during school vacation week. He is finishing a house and there are some jobs that Travis can help him with. Travis is thrilled. He can hardly wait for the first day, and after what feels like forever, it has finally arrived. Travis and Uncle Larry arrive at the site. They are going to be working on finishing a part of a wall. When they arrive, there are bunch of boards and tools waiting for them. Here is the dilemma. Two wall studs have already been nailed into the floor. Travis and Uncle Larry need to add in the brace that goes 00 0 between the two studs. The space between the wall studs measures 43 58 . The board that they wish to use is 4 12 long. “Travis, this is your first task,” Uncle Larry says. “While I go and check on some other work, I need you to do a few estimations. First, figure out if the board we have will fit. Then, figure out how much of the board we need to cut off to fit between these two wall studs. Do you have any questions?” “Nope,” says Travis getting out a piece of paper and a pencil. Travis knows how to figure this out, do you? Well, if you don’t, you will by the end of the Concept. This Concept is all about estimating with fractions and whole numbers. Pay close attention, we come back to solve Travis’ problem later! Guidance We can also estimate by rounding mixed numbers. Remember that a mixed number is a number that has a whole number and a fraction. A mixed number refers to a number that is between one whole number and another. 1 www.ck12.org How do we round mixed numbers to the nearest whole? To do this, we need to look at both the whole number part of the mixed number and the fraction part of the mixed number. The whole will tell us which two numbers the fraction part is between. 5 16 is found between the whole numbers 5 and 6. Our answer is 5. 5 16 is closer to 5. In the example we just looked at, one-sixth is a very small fraction. If the fraction part of the mixed number had been one-half or greater, then we would have said that five and one-sixth was closer to six. We can think in this way whenever we are rounding mixed numbers. Practice by rounding these mixed numbers. Example A 7 69 Solution:8 Example B 4 41 Solution:4 Example C 5 6 10 Solution:7 Now back to the dilemma. Two wall studs have already been nailed into the floor. Travis and Uncle Larry need to add in the brace that goes 00 0 between the two studs. The space between the wall studs measures 43 58 . The board that they wish to use is 4 12 long. “Travis, this is your first task,” Uncle Larry says. “While I go and check on some other work I need you to do a few estimations. First, figure out if the board we have will fit. Then, figure out how much of the board we need to cut off to fit between these two wall studs. Do you have any questions?” “Nope,” says Travis getting out a piece of paper and a pencil. The first thing to notice is that the space is being measured in inches, and the boards are being measured in feet. Let’s change the feet to inches first. 0 4 12 = 4800 + 600 = 5400 is the board length. 2 www.ck12.org Chapter 1. Mixed Number Rounding to the Nearest Whole 00 The space measures 43 58 . The first thing that Uncle Larry wanted Travis to figure out was if the board would be long enough to fit the 00 space. 54” is greater than 43 85 , so it will work, but the board will need to be cut. To figure out how much board to cut, we need to find a difference. We can estimate the difference by rounding. 54” is already a whole number. 43 85 is closest to 44. We round it up to 44”. 54 − 44 = 1000 . Travis and Uncle Larry will need to cut approximately 10” from the board to have it fit into the space. Fractions and mixed numbers are used all the time in real life dilemmas like Travis’. Contractors use fractions all of the time! Vocabulary Fraction a part of a whole written with a fraction bar, a numerator and a denominator. Estimate to find an approximate answer that is reasonable and makes sense given the problem. Mixed number a number made up of a whole number and a fraction. Sum the answer to an addition problem. Difference the answer to a subtraction problem. Guided Practice Here is one for you to try on your own. Sarah is helping to measure a hem on a dress. She measures that the dress needs to be shortened 6 12 16 inches. Given this measurement, does it make sense for Sarah to round down to 6 or up to 7 inches? Answer Given that 12 16 is greater than one - half, it makes sense to round up. Sarah should round up and shorten the dress by seven inches. Video Review MEDIA Click image to the left or use the URL below. URL: http://www.ck12.org/flx/render/embeddedobject/5369 Estimating with fractions - This is a secondary skill to this Concept. It involves estimating with fractions. 3 www.ck12.org Explore More Directions: Round each to the nearest whole number. 8 1. 3 10 2. 1 23 3. 5 56 4 4. 6 13 5. 11 75 6. 26 59 2 7. 14 11 1 8. 13 10 6 9. 17 13 10. 19 47 11. 21 11 12 12. 34 12 25 13. 46 16 24 14. 21 18 20 15. 9 19 30 4

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