Teaching Borrowing in Subtraction
Date: 03/12/97 at 22:52:28 From: S. K. Anania Subject: Second graders and 2-digit subtraction I teach second grade. Some students are becoming very frustrated with the concept of tens and ones when regrouping. I'm sure they haven't grasped tens and ones but I'm forced to move on. What kind of remedial suggestions do you have? We have been on manipulatives. I do have students explain their methods. We demonstrate on the overhead. I have imformed parents. Yes, these are some of the same students who don't readily know their basic facts. I appreciate any suggestions.
Date: 03/14/97 at 11:15:09 From: Doctor Barney Subject: Re: Second graders and 2-digit subtraction Get several boxes of toothpicks and lots of those twist-ties used to keep plastic bags shut. Give students between 11 and 99 toothpicks each and have them tie up bundles of ten toothpicks. Explain that the number of bundles is the tens digit, and the number of loose toothpicks is the ones digit. Now ask them to give you back (subtract) a number which requires borrowing. When they have to unbundle one of their sets of ten toothpicks the concept should be a little clearer. May your patience be rewarded with enlightenment. -Doctor Barney, The Math Forum Check out our web site! http://mathforum.org/dr.math/
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.