Mixed Number Rounding to
the Nearest Whole
Jen Kershaw
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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.
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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.
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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.
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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