Another breakthrough

Today at breakfast, Jiaheng was looking intently at the orange box on the dining table.



It is for some sachets of powder used to make an alkaline drink. Just got it from mum this morning, so it is the first time Jiaheng saw it. So maybe that explains why he is so interested in the box. After some time, Jiaheng told me "Mommy, it is correct. " "What is correct, Jiaheng?" I asked.

"Mommy, you see here. (pointing at the bottom left corner of the packaging) It says 112 g NET. And it is correct."
"How do you know, Jiaheng?"
"Well because xxgsgdeg kdsgj adikg adklgj ... that is why it is 112 g"

Jiaheng said a series of things which included some multiplication and some adding and some subtraction in it. At that time, I was still not in the right frame of mind to really catch his argument. So I asked him to hold on and let me get a piece of paper to write down what he said.

While he repeated his argument again, I quickly scribbled down some notes so that I can verify it. Here is how it looks like

How? Can catch any ball? Ermmphh! Let me decode the "Jiaheng-vinci code" for you.

On the box, it was stated 112 g NET, 28 sachets each 4 g NET.

That was why he got 4 x 10 = 40 (for 10 sachets), then he went on to get the total for 30 sachets (i.e. 40 x 2, 40 x 3 = 120g). But 30 sachets are too much, so he used his abacus formula to deduct 4 g (-10+6) and then deduct another 4 g (+1-5). Finally 112 g.

Well, this definitely is not the quickly or least number of steps way of getting 112. However, it did amaze me in the way his mind is able to handle multiple steps and doing all those multiplication, addition and subtraction all at one go. :)

Then I said, how else can we get 112? What about 28 x 4? And he said yes, it will be 28 + 28 + 28 + 28. Also can, he concluded.

So after checking and doing double checking, Jiaheng is now very happy with his own conclusion that the printing on the box is "mathematically correct"! (of course lah, son) And carried on with his breakfast.

To me, it is another breakthrough for him to handle such complex sums even before turning 5. Good job, son. Love you.

----------- posted by Mommy