Sohn has never understood "regrouping" in subtraction. Example: 45-37 is really confusing because he didn't understand how to move 10 to the 5 worth 15 (making the 4 a 3).
His teachers were never able to explain this concept in a way that he could understand, and as much as I tried to explain it I have not been successful either.
Until today. My math goal for this week was to explain this concept in a way that he would understand. I dumped a handful of dimes and pennies onto the counter and asked him to use them to represent the number 63. (6 dimes, 3 pennies) On a sheet of paper, I wrote the number 63. Then I crossed out the 6 and wrote a 5, and turned 3 into 13. I moved one dime away, but added 10 pennies. "Is this still 63 cents?" Yep. Making progress. After a few more examples, we moved on. Talked about the "tens column" and the "ones column" and how we can move from one to the other- demonstrated with coins. Then we moved on to subtraction... and the concept makes sense!
I asked him if he wanted me to print some subtraction worksheets, or if he just wanted to use the online math program & he chose the online. First question he was given was 3 digit subtraction (659-491) and he had the right answer before I had finished writing the question on my scratch pad. The kid is a math whiz- does mental math faster than I can use my calculator!
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