Homeschool Math, www.HomeschoolMath.net website logo

Home | Blog | Amazon Store | Newsletter  

Ebooks | Worksheets | Curriculum Guide | Lessons & Articles | Reviews |
May newsletter     An online tutor helps you teach math at home!

The ideas in this borrowing lesson are taken from Add & Subtract 2-B ebook. Only a few examples of each problem type are shown; you should make more problems of each kind for the student.


Subtracting in columns - borrowing
Free lesson plan from ebook Adding & Subtracting in Columns 1

This lesson aims to explain the idea of borrowing. The student is first made to notice that sometimes when subtracting you don't have enough ones to do the 'taking away'. The solution is to break down one ten into ten ones.  This process is first practiced with pictures (or manipulatives).  

45 − 7 = ?

 

 



4 tens and 5 ones

3 tens and 15 ones

 

In the first picture, we can't cross out 7 ones, so we break down one ten-pillar. Now cross out 7 ones.  What is left?

__ tens and __ ones =____

42 − 18 = ?

 

 



4 tens and 2 ones

__ tens and __ ones

 

In the first picture, we can't cross out 1 ten and 8 ones, so we break down one ten-pillar.  Now cross out 1 ten 8 ones.  What is left?

__ tens and __ ones =____



Example exercise types

These are just examples of the type of problems to do.  You should provide much more practice than is shown here.

1.  Break down a ten.  Draw ten-pillars and ones.  What do the numbers become?

 

43

4 tens 3 ones  

3 tens 13 ones

 

36

__ tens __ ones  

__ tens __ ones

Do it also without the pictures.

24

__tens __ones      __tens __ones

82

__tens __ones      __tens __ones

 

2.  Break down a ten first.  Then subtract ones and tens separately.  Write down the subtraction sentence.

5 tens 5 ones

−  1 ten  7 ones

 

4 tens 15 ones

−  1 ten    7 ones

3 tens   8 ones

    55 − 17 = 38


After practicing for a while the process of breaking the ten into ten ones, it is time to introduce the standard form of subtracting in columns.

 

 



5 tens and 3 ones

__ tens and __ ones

Cross out 1 ten 6 ones.  What is left?     __tens __ ones

tens
4

ones
13

 5

3

  1 

6

 

 3 

 7 

      The '5' in the tens-column changes into 4  because we
'broke one ten down'  OR BORROWED one ten into
the  ones-column.  Now the ones-column has 13
instead of just 3.  

Then we subtract the ones and  the tens separately.


4 tens 

__ tens and __ ones

Cross out 2 ten 8 ones.  What is left?     __tens __ ones

tens
 

ones
 

  

 

  2

8

 

  

  

     

We borrow a ten into the ones-column.  
Now the tens-column has __ left, and ones-column
has __ instead of just __.  

Then we subtract the ones and the tens separately.


Example problems

1.   Fill in the table.  Break one ten down, then subtract.

4 tens 3 ones  = 3 tens 13 ones

Take away 1 ten 7 ones.

What is left?

__ tens and __ ones

3

13

 4 

3

 1

7

 

  

  

5 tens 2 ones  = __ tens __ ones

Take away 2 tens 7 ones.

What is left?  

__ tens and __ ones

 

 

 5 

 2

7

 

  

  

2.  Subtract.  Borrow from the tens when needed.

56
− 47

 

90
− 28

 

42
− 11

 

91
− 53

 

55
− 17

 

 

   Figure out the missing numbers in these subtraction
   problems! You might need to borrow from the tens.

    

 3 

 1

 


7   5  

 8 

    

 

 7 


1   6  

    

 0 

 3 

 


4   2  

  

  

 1

 4


6   8  

 6 

 2 

 

 


5   3  

 

FREE math homework help on www.PhatMath.com
  • 40 Math forums for grades K-12 & College
  • Post/view math problems & solutions
  • Blogs for students, parents, teachers


Download my
Geometry workbook with lots of hands-on drawing problems!





Times Tales

Learn the upper
times tables with
mnemonic stories.

Learn more!




 

 

 

Teaching Tips and Math Lessons menu

All grades

Teaching math
Is your curriculum coherent?
How to motivate & prevent math anxiety
Keeping math skills sharp in the summer
Setting up equations for word problems
Interview with an astronomer
ADD/ADHD and diet
Omega-3 fats & intelligence

Elementary

Using calculator in elementary grades?
Teaching word problems

Middle

Balance illustrates equation solving
Why are fractions so difficult?
Negative or zero exponents
Number to zero power is one - 2 proofs
How to teach proportions
How to teach integers
Hands-on with pi
Sine in a right triangle
Rational numbers & converting repeating decimals into fractions
Why study math? square roots? algebra?
Square roots without a calculator?

High School

Why high school geometry is difficult
Help with high school geometry
What is proof?
Two-column proof vs. paragraph proof
Proving is a process - logarithm problem
Fascinating irrational numbers
Proof that square root of 2 is irrational
Rational numbers are countable
How does calculator find values of sine?
Fibonacci numbers and golden section
Why does the square root algorithm work?



HOMESCHOOL MATH NEWSLETTER

Homeschool Math Newsletter comes out once monthly, and includes math teaching articles and tips, Math Mammoth news, and all kinds of little "tidbits" such as math news, interesting links, or humor. The content is equally good for all of us who teach math (not just homeschooling parents).

When you subscribe, you will alsoreceive a GIFT of over 280 FREE math worksheets and sample pages from Math Mammoth books for grades 1-8.

Note: This is a double opt-in list. You will FIRST get an email that asks you to confirm your email address. PLEASE check also your SPAM/JUNK folder for this confirmation email.

Take a peek at the previous volumes here!.

The newsletter service is by Aweber.com. Your email address will not be shared, sold, or distributed to anyone else.

Google

Download 280+ QUALITY math worksheets
Link to us    Sitemap    Contact    About    Privacy    Advertise    Homeschool links    Educational links
Best Homeschool Sites on the Internet - Homeschool Top Sites
Copyright 2003-2008 Homeschool math
http://www.homeschoolmath.net/


 

 

P.S. ....

 

Check out these short video clips from my favorite band - Rockabilly.US. They play oldies, Elvis, country, and top hits of the 50s and 60s. It's a show with large band, costumes, choreography, little skits, "Kid Kritters", 6 dancing/singing girls, junior dancer troupe, etc.

"Be My Baby"
originally by the Ronettes

Impossible Dream (Elvis song)
Most importantly, the band wants to use the uplifting and energetic music to bring some fun, happiness and encouragement into people's lives. They're doing it selflessly to help others, and don't get paid for any of it themselves. And I admire that!

=> See more video clips at YouTube