# Interactive video lesson plan for: Subtracting decimals-Mistake Proof Method

#### Activity overview:

Step by step directions for subtracting decimals.
I use graph paper to help organize the numbers and avoid mistakes.
The key to subtracting decimals is to always have the decimals lines up.
Transcript
Welcome to moomoomath where we upload a new Math video everyday.
In this video I would like to talk about subtracting decimals.
I call this the no mistake method.
Many times when we subtract decimals it can be confusing figuring out where the decimal should be and what numbers you should subtract.
What you can do is use graph paper at least at first until you get a hang of this and it helps you keep all of your rows organized.
Lets get started.
I will make this column the decimals and I will write 2.5 and when you subtract you keep the decimals lined up and i will write .076 here.
Now what I will do is for each block I will write in a zero.
This helps you visualize what you are subtracting.
I next start subtracting and I can't subtract from zero so I will borrow 10 and I have another zero so I can't borrow there so I will move to the 5 and it will become a 4 and this will become a 10 and I will borrow and this number becomes a 10 and the number to the left becomes a nine.
10-6 = 4
9-7=2
4-0=4
and bring down your 2 so you end up with 2.424
This next example of subtracting decimals requires some rewriting.
We have .564 minus 2.632
I will write 2.632 first because it is larger and just subtract but keep the sign of the larger number.
12-4 = 8
We need to borrow.
12-6 =6
5-5 = 0
Write the decimal point and bring down the 2
and it becomes - 2. 068
Let's finish with one more.
This last one and it is different because you have 3 numbers to subtract.
I will write three decimals.
I will write the 3 then -1.02 and then the .654
I will write zeros everywhere else.
I now start subtracting
Again I need to borrow 10 and I will borrow the 10 from the 3.
This becomes 10 and the next zero will become a 9 and we have,
10-4 =6
9-2=7
9-6=3
Bring down the decimal
and 2-1=1
We end up with 1.326
Recap I use the graph paper because it help me line up the columns and prevent mistakes.
MooMooMath uploads a new math video eveyday.
Thanks for watching.

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Tagged under: decimals,subtracting decimals,numbers,math,moomoomath,subtracting decimals mistake proof method,maths,subtraction,addition

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