Subtracting Decimals Explained: A Step-By-Step Review | Understanding Decimal Subtraction
Summary
TLDRIn this educational video, Mr. J offers a concise review of decimal subtraction, ideal for middle school, high school, college, and adult learners. He demonstrates how to align decimals and use placeholder zeros for clarity, guiding viewers through two detailed examples. The video highlights common mistakes to avoid, such as not borrowing when necessary, and emphasizes the importance of accuracy in decimal subtraction.
Takeaways
- 📚 The video provides a quick review of subtracting decimals, suitable for middle school, high school, college, and adult learners.
- 🔢 To subtract decimals, align the decimal points to ensure proper place value alignment.
- 💡 Use placeholder zeros to make the decimals align neatly, especially when dealing with different decimal places.
- 🚫 Avoid the common mistake of dropping the zero in the hundredths place without borrowing, as this can lead to incorrect results.
- ✏️ When subtracting, start from the rightmost digit (hundredths place) and move left, borrowing as necessary.
- 📉 Subtract decimals vertically, similar to how you would add them, to maintain alignment and accuracy.
- 🔄 Remember that borrowing changes the value of the digits above; for example, borrowing from the tenths place changes a '9' to an '8'.
- 📈 After borrowing, subtract the new values in each place value, moving from the hundredths to the ones place.
- 💯 The final answer should have the decimal point aligned with the original problem, maintaining the decimal places.
- 📝 Practice is key to mastering decimal subtraction, and the video offers examples to help viewers understand the process.
Q & A
What is the main topic of the video?
-The main topic of the video is a quick review of subtracting decimals.
Who is the target audience for this video?
-The target audience includes middle school, high school, college students, and adults continuing their education.
What is the first example problem presented in the video?
-The first example problem is subtracting 8 and 57 hundredths from 14 and 9 tenths.
Why is it important to line up the decimals when subtracting?
-Lining up the decimals ensures that all the corresponding place values are aligned, making the subtraction process accurate and straightforward.
What is the purpose of using placeholder zeros in decimal subtraction?
-Using placeholder zeros helps to align the decimal places correctly and avoid mistakes, especially when one number has fewer decimal places than the other.
What is the common mistake to avoid when subtracting decimals?
-The common mistake to avoid is not borrowing correctly when there is a zero in the higher place value of the decimal. One should not simply drop the zero and proceed with the subtraction.
How does borrowing work in the context of the first example problem?
-In the first example, borrowing is needed when subtracting in the hundredths place (0 minus 7) and the ones place (4 minus 8). The tens place is borrowed from to provide a value for subtraction.
What is the final answer to the first example problem in the video?
-The final answer to the first example problem is 6 and 33 hundredths.
What is the second example problem in the video?
-The second example problem is subtracting 59 and 8 tenths from 262 and 33 hundredths.
How is the decimal point handled during the subtraction process?
-The decimal point is brought straight down into the answer after aligning the decimals and performing the subtraction in each place value.
What is the final answer to the second example problem in the video?
-The final answer to the second example problem is 202 and 53 hundredths.
Outlines
📘 Subtracting Decimals Tutorial
This paragraph is a tutorial on subtracting decimals, aimed at various educational levels. The instructor begins by emphasizing the importance of aligning the decimal points when performing subtraction, using the example of 14.9 - 8.57. To avoid mistakes, the instructor suggests using placeholder zeros to align the numbers properly. They demonstrate the subtraction step by step, borrowing from the left when necessary, and highlight a common mistake of not borrowing when a zero appears in the higher place value. The solution to the example is 6.33.
🙌 Conclusion and Sign-off
The second paragraph is a brief conclusion and sign-off from the instructor. They thank the viewers for watching the tutorial on subtracting decimals and express a friendly farewell, indicating the end of the video.
Mindmap
Keywords
💡Decimals
💡Subtracting
💡Aligning
💡Placeholder Zeros
💡Borrowing
💡Tenths
💡Hundredths
💡Common Mistake
💡Equivalent Decimal
💡Vertical Subtraction
💡Decimal Point
Highlights
Introduction to subtracting decimals for various educational levels.
Importance of lining up decimals when subtracting to align all places properly.
Use of placeholder zeros to make decimal alignment clearer, without affecting the value.
Detailed breakdown of example 1: 14.9 - 8.57.
Borrowing explained: From tenths to hundredths place when performing subtraction (zero minus seven).
Clear steps for handling zeros and the significance of borrowing in subtraction.
Common mistake warning: Dropping digits during subtraction without borrowing can lead to incorrect results.
Detailed breakdown of example 2: 262.33 - 59.8.
Importance of using placeholder zeros again in the second example.
Borrowing from tenths place to hundredths in the second example.
Explanation of borrowing across places: borrowing from ones place to subtract in the second example.
Final answers for both examples demonstrated: 6.33 for the first and 202.53 for the second.
Encouragement to always use placeholder zeros to prevent mistakes.
Reminder to align the decimals correctly before performing any subtraction.
Conclusion with a recap of tips: Line up decimals, use placeholder zeros, and carefully borrow when needed.
Transcripts
[Music]
welcome to math with mr j
[Music]
in this video i'm going to go through a
quick review of subtracting decimals
this should be helpful for anyone
looking for a quick refresher whether
you're in middle school high school
college continuing your education as an
adult really no matter what class or
goal you are working towards here are a
couple of examples to get this down
let's jump into number one where we have
14 and 9 10 minus 8 and 57 hundredths
now just like when we add decimals when
we subtract decimals we need to line the
decimals up that's going to line up all
of our places so let's rewrite this
first problem vertically here lining up
the decimals so fourteen and nine tenths
minus
eight
and fifty-seven hundredths
so the decimals are lined up and that's
going to line up all of our places now
that problem looks a little offset
because 14 and nine-tenths goes to the
tenths place and then eight and 57
hundredths goes to the hundredths place
so just like when we add decimals we can
use placeholder zeros to have this look
more lined up so let's use a placeholder
zero in the hundredths place here and
then both of our decimals go to the
hundredths place remember zeros to the
right of a decimal do not change the
value that's an equivalent decimal and
does not change the value of the problem
at all now we're able to subtract so
we'll start with the hundredths place we
have zero minus seven which we need to
borrow so let's borrow from the nine
that's an eight now
and we have ten minus seven which is
three
then we move to the tenths place eight
minus five
three
bring our decimal straight down into the
answer the decimal is lined up
throughout the entire problem then we
move to the ones place four minus eight
we need to borrow from the tens place
here so that's a zero
and that's a fourteen so fourteen minus
eight is six
and we are done
six
and thirty three hundredths
now i do wanna mention one more thing
before moving on to number two and this
is going to be a common mistake that
you'll want to avoid and using
placeholder zeros will actually help you
avoid this mistake so let me rewrite the
problem here
real quick to the side so we have 14
and nine tenths minus
eight
and 57 hundredths
so dropping this 7 so starting with the
hundredths place and then just dropping
the 7 because there isn't anything above
it
is not correct we actually have zero
minus seven there
so we needed to borrow and you can see
we do not have a seven in the hundredths
place in our final answer so again avoid
the mistake of just dropping that number
because really we have zero minus seven
there and we need to borrow so be
careful of that
let's move on to number two where we
have
262 and 33 hundredths minus 59 and eight
tenths
so we will start by lining up our
decimals here
so
262 and 33 hundredths minus
59
and eight tenths
we can use a placeholder zero so these
both go to the hundredths and now we are
able to subtract so we'll start with the
hundredths three minus zero is three
the tenths place three minus eight well
we need to borrow so borrow from the two
that's a one
and we have a thirteen so thirteen minus
eight is five
we can bring our decimal straight down
into our answer
and now we have the ones place so 1
minus 9 we need to borrow so we'll
borrow from the 6
and we have 11 minus 9 which is
2.
then for the tens place we have 5 minus
5 which is 0.
and then lastly we have the hundreds
place where we have 2 minus nothing
under it so it's just two minus zero
which is two
and our final answer two hundred two and
fifty three hundredths so there you have
it there's a quick review of subtracting
decimals line the decimals up
use placeholder zeros if need be and
then subtract
i hope that helped
thanks so much for watching
until next time
peace
you
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