tag:blogger.com,1999:blog-5255877501892467740.post2653062692327361974..comments2014-10-25T21:28:43.606-04:00Comments on Craft Knife: Montessori Math: Building Big Numbers with Base Ten Blocksjuliehttp://www.blogger.com/profile/18141123092139829629noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-5255877501892467740.post-73531978945282566832012-01-28T20:49:11.423-05:002012-01-28T20:49:11.423-05:00I've just finished a first read of "Child...I've just finished a first read of "Children Continue to Reinvent Arithmetic: Grade Two" by Constance Kamii. There's a lot in there about how mindlessly learning an algorithem for multi-digit adding and subtracting can essentially wipe out any prior understanding kids had of place value. So, you're totally on the right track with all the hands-on stuff. Your kids will actually know what the numerals stand for! :)Malkehttp://www.mathinyourfeet.blogspot.comnoreply@blogger.comtag:blogger.com,1999:blog-5255877501892467740.post-153064036420508052012-01-28T10:03:50.944-05:002012-01-28T10:03:50.944-05:00When I watched the Khan Academy video of subtracti...When I watched the Khan Academy video of subtraction with borrowing with Will recently (I'm ashamed to admit that I had forgotten exactly how to do it when you have to borrow from more than one place value at a time), I realized that the video was the first time, in all of my schooling, that I remember somebody explaining the CONCEPT behind borrowing--you know, WHY it works! If all I was taught was the shortcut (borrow a 1 from the next place value), then of course I forgot how to subtract, because all you have to do is forget the context-less shortcut and the entire skill is lost. If you understand the physical concept of how borrowing from a higher place value works, then even if you forget the shortcut of borrowing a one, then you can still figure your way through subtracting big numbers.<br /><br />Basically, what I'm trying to say is that I seem to be learning math right along with Willow.juliehttp://www.blogger.com/profile/18141123092139829629noreply@blogger.comtag:blogger.com,1999:blog-5255877501892467740.post-63498191177251281912012-01-27T21:57:54.077-05:002012-01-27T21:57:54.077-05:00Thanks for this post! Math scares me, and I think ...Thanks for this post! Math scares me, and I think you just made it a little less scary. Of to order some stuff from amazon!Tinahttp://www.blogger.com/profile/09611764295297526639noreply@blogger.com