1) I wanted to say how COOL I think "Terry's way to subtract" is. I'm a certified math whiz, award-winning mathlete who *almost* went into mathematics professionally. And I had never thought of this way of doing subtraction instead of 'borrowing'. Once I understood it, I can now do big-number complex subtraction in my head, much more easily than with borrowing.

2) When it comes to the parts of the subtraction where there are "not enough" so you subtract from the answer instead of add... I was curious what your original intention was for how to come to that part of the answer. I saw it as going "backwards" -- subtracting UP instead of DOWN, and so using - instead of + because I'm going the 'wrong way', the 'opposite' way. When I introduced this to my son, HE figured it out as still subtracting the normal way, but writing the NEGATIVE number which was the answer. eg -- if it's 57-38, the 7-8 part, I would do 8-7=1 so subtract one from the answer. He saw it as 7-8= -1, so add -1 to the answer.

Of course, both arrive at the correct answer. I thought my way is faster and easier, and his way is more mathematically rich and complex (so very fascinating that he saw it that way), but not as quick and easy. So I know it doesn't really MATTER but I'm curious what the intended way was, if there was one.

3) I see other posts where people talk about playing Corners to 1000, or in the basic instructions where it says to play until the cards run out. Corners is, so far, DS's favourite game... and we've never yet had a game get past about 150 or so, and have never got through the whole deck, because we get 'stuck' where neither player can move.

We tend to play the corners a lot -- I know it says that 'beginning players will tend to ignore the corners' but we're not lol... I think this makes us get stuck more because we end up limiting our free edges to play on. Is this all it is, or have I misunderstood something in the rules?

Hello Heather,

I am glad that you are enjoying finding new ways to see how math works.

In my opinion, I have to say that subtraction is one of the most mis-taught elementary foundations of mathematics. They teach it as going backwards on a number line, but clearly as you and your son are learning, it is more than that.

Subtraction can be going forward or backwards, it can be positives and negatives, it can be remainders or differences.

The way it is taught in most curriculums gives a very limited scope as to the true nature of subtraction. As you discovered you both of you do it differently, and that is okay, if the answers are usually correct. It is true some ways may seem faster then other ways, but not if your brain is not organized to solve it that way. For instance, some people struggle going backwards, thus subtracting by going forward is the most efficient way to solve it. Nevertheless, you should expose them to all the different ways to problem solve so that they are always aware that there is more than one way to solve the same problem. This training now will help them immensely in the higher math levels.

So keep up the good work and keep showing him all the ways he can solve it, then let his mind do the one that comes more natural to him.

As far as corners, we love that game too. To play up to a thousand, you just keep the score going. For example, you play day one, and say you end at 155 points. Tomorrow you start a new game and start with the points 155. Then start the next game with the points you ended with the last time, until you come to 1000. For my family, we take SERVAL days to get to the 1000 points. Or we Start at 1000 and go down to zero. but it is a series of days, not just one event. That would take WAY too long.


Please let me know if you have any more questions. You can email me directly at Carissa@alabacus.com .

Thank you for giving your child a RightStart in Math,

Carissa
RightStart™ Mathematics by Activities for Learning, Inc.

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Our Mission: To help children understand, apply, and enjoy mathematics

"As far as corners, we love that game too. To play up to a thousand, you just keep the score going. For example, you play day one, and say you end at 155 points. Tomorrow you start a new game and start with the points 155. Then start the next game with the points you ended with the last time, until you come to 1000."

Ahhhh okay. For us it wasn't a matter of taking up too much time -- just that the game would end because no more moves were possible. But I like that idea of adding games together for a mega-score. :)