Join the Meeting Place for Moms!
Talk to other moms, share advice, and have fun!

(minimum 6 characters)

Subtraction With Borrowing

Posted by on May. 6, 2012 at 4:52 PM
• 6 Replies

My daughter can add like there is no tomorrow, but subtraction seems to  be a different story :/. She can do fine if it's a problem like 19-8, but not 18-9. She automatically flips the 9 to the top so to her the problem is still 19-8 and she'd answer 11. I have tried just about everything I can think of including doing it on a marker board so it's larger with stickers, I've tried manipulatives, I've tried number flash cards so we can break the problem apart more. Any advice?

by on May. 6, 2012 at 4:52 PM
You must be a member to reply to this post.
Replies (1-6):
by on May. 6, 2012 at 5:26 PM

Have you tried to teach her "how far apart are these numbers"?

18-9....How far is it from 18 down to 10?  Child usually answers 8.  How far is it from 10 down to 9?  Child will say 1.  What is 8 plus 1?

You can also do the reverse...how far is it from 9 up to 10?  Then how far is it from 10 up to 18.  Add the answers together.

by on May. 6, 2012 at 11:36 PM

I worked really hard on teaching my DD place value and went about it alot of ways so she could really wrap her brain around it. First I taught her how to master finger counting. So using your example I would say "ok first think 18 in your head, then lets count down 9". Then we both hold our fingers up and do it together, say 18, put a finger down each number 17, 16 down to 9. Then we announce it is 9!! Then when starting this process we would count back up to check. Think 9 in your head, hold up 9 fingers then count up 10-11-12 until 18. Yes it works.

I also hunted and found counting blocks. I got a bag of 1 units, 10 units, 100unit, and 1000 block. So in that same example I would help set it up 1 10-block and 8 1-blocks. Then I would say take away 9. She would removed the 8 and say she cant. So I showed how we turned 10block into 10 1-unit blocks by trading it out or 'borrowing'. Then she had 18 1-unit blocks and could easily remove 9, then counted that 9 remained.

To reinforce how the blocks work we would add bigger numbers. If she had something that was over 10 she had to trade the 10 1-blocks for a 10-block. Then I drew it out on a dry erase board the tens place and ones place. We did lots of example and using the blocks.

Just recently we finished money unit. To make change I let her use the blocks. It helped so much. She is so fast at adding and subtracting and has now easily memorized the under 10 stuff like 4+2. OH b-t-w I looked on craigslist, ebay, and lots of used book stores before I found the blocks in a corner of a homeschool used book store.

by on May. 7, 2012 at 8:58 AM

I agree with getting counting blocks. We are going to start this soon. Eeek!

by on May. 7, 2012 at 9:00 AM
Honestly, this is a common issue. I recomment taking a break from subtraction and moving on to basic multiplication then doing subtraction right before division.
by Silver Member on May. 7, 2012 at 12:50 PM

Thank you everyone :)
We do use blocks and other manipulatives. We have done both counting up and counting down with fingers and manipulatives and she has mastered place value. I have tried teaching her what we called "shortcuts"  where we try to get as close to 10 or five and then adding, but that confused her more I think so we stopped with that method for now.
We're starting with the Math U See program next year using the Gamma Book so we'll be doing multiplication next year for sure. I have introduced it and planned on working on it a little more until next year since she stresses over new subjects (this just recently started too). Taking a break doesn't sound like a bad idea though for a while :)

by Sonja on May. 7, 2012 at 3:44 PM

I agree with kickbutt. You should first take a break and then go with doing the multiplication tables.  My daughter had the same issue and we did the same thing. When we came back to the subtraction, she was able to understand more subtraction than before we stopped.  :)

Quoting KickButtMama:

Honestly, this is a common issue. I recomment taking a break from subtraction and moving on to basic multiplication then doing subtraction right before division.