Comments on: How do I teach subtraction with regrouping of zeros? http://www.mathstudenthelp.info/subtraction/how-do-i-teach-subtraction-with-regrouping-of-zeros Let us help you add it up! Sun, 12 Feb 2012 08:43:18 +0000 http://wordpress.org/?v=2.7 hourly 1 By: eastacademic http://www.mathstudenthelp.info/subtraction/how-do-i-teach-subtraction-with-regrouping-of-zeros/comment-page-1#comment-6964 eastacademic Wed, 02 Dec 2009 03:48:59 +0000 http://www.mathstudenthelp.info/subtraction/how-do-i-teach-subtraction-with-regrouping-of-zeros#comment-6964 have him do 23 minus 7 with crackers. use small goldfish for the ones, and saltines for the tens. So he gets 2 saltines and 3 fish. As soon as you tell him the saltine is worth 10 fish - he will see that he can borrow by "trading it in" to you - so he can subtract 7 from his grouping. He should then be able to see why you have to borrow from each spot. look up more on place value if you want to find some other activities for his level.<br><b>References : </b><br> have him do 23 minus 7 with crackers.

use small goldfish for the ones, and saltines for the tens.

So he gets 2 saltines and 3 fish. As soon as you tell him the saltine is worth 10 fish - he will see that he can borrow by "trading it in" to you - so he can subtract 7 from his grouping.

He should then be able to see why you have to borrow from each spot. look up more on place value if you want to find some other activities for his level.
References :

]]> By: joybells http://www.mathstudenthelp.info/subtraction/how-do-i-teach-subtraction-with-regrouping-of-zeros/comment-page-1#comment-6963 joybells Wed, 02 Dec 2009 03:12:59 +0000 http://www.mathstudenthelp.info/subtraction/how-do-i-teach-subtraction-with-regrouping-of-zeros#comment-6963 I would get 100 pennies, put them in piles of 10. Then have your brother take away (subtract) 50 pennies or 5 piles of 10. Then write it out in numerals. 100 - 50 = 50 Show him the five stacks of pennies left and point to the numerals. Put the 100 pennies back into a group and then have him try to subtract 59. He will have to break one of the piles of 10. Hopefully he will get the picture. If you can gather 1000 pennies you could have him take away $5.99. You could use pennies, popsicle sticks or pieces of paper, whatever you have around. If he understands money, try to help him understand that when you buy something for 99 cents that you get 1 penny back, which explains the .01. Then do 5.99 from 10 dollars.<br><b>References : </b><br> I would get 100 pennies, put them in piles of 10. Then have your brother take away (subtract) 50 pennies or 5 piles of 10. Then write it out in numerals. 100 - 50 = 50 Show him the five stacks of pennies left and point to the numerals. Put the 100 pennies back into a group and then have him try to subtract 59. He will have to break one of the piles of 10. Hopefully he will get the picture. If you can gather 1000 pennies you could have him take away $5.99. You could use pennies, popsicle sticks or pieces of paper, whatever you have around.

If he understands money, try to help him understand that when you buy something for 99 cents that you get 1 penny back, which explains the .01. Then do 5.99 from 10 dollars.
References :

]]> By: Common Sense http://www.mathstudenthelp.info/subtraction/how-do-i-teach-subtraction-with-regrouping-of-zeros/comment-page-1#comment-6962 Common Sense Wed, 02 Dec 2009 02:23:59 +0000 http://www.mathstudenthelp.info/subtraction/how-do-i-teach-subtraction-with-regrouping-of-zeros#comment-6962 When you run into multiple zero you repeat the algorithm you would normally do, until you run out of zeros. Hopefully the following will explain why. Lets start with a single zero example: If you had 30-4 you would rearrange it to (20 + 10) - 4 = 20 + (10 - 4) =20 + 6 = 26 The same works for multiple zeros 300 - 4 = (200 + 100) - 4 = (200 + 90 + 10) - 4 = 200 + 90 + (10 - 4) = 200 + 90 + 6 = 296 One last example to drive the point home 300 - 46 = (200 + 100) - (40 + 6) = (200 + 90 + 10) - (40 + 6) = 200 + (90 - 40) + (10 - 6) = 200 + 50 + 4 = 254 In school children are taught this, just in a shorter form. Hope this helps.<br><b>References : </b><br> When you run into multiple zero you repeat the algorithm you would normally do, until you run out of zeros.

Hopefully the following will explain why.

Lets start with a single zero example:
If you had 30-4 you would rearrange it to
(20 + 10) - 4
= 20 + (10 - 4)
=20 + 6
= 26

The same works for multiple zeros
300 - 4
= (200 + 100) - 4
= (200 + 90 + 10) - 4
= 200 + 90 + (10 - 4)
= 200 + 90 + 6
= 296

One last example to drive the point home
300 - 46
= (200 + 100) - (40 + 6)
= (200 + 90 + 10) - (40 + 6)
= 200 + (90 - 40) + (10 - 6)
= 200 + 50 + 4
= 254

In school children are taught this, just in a shorter form.

Hope this helps.
References :

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