Hi,
Does anyone have any suggestions for teaching the concept of rounding to 10’s, 100’s, 1000’s, 10,000’s? My son is in 3rd grade (9yrs old) and is having a great deal of trouble with this. I thought he understood the concept of place value, but now it is clear he doesn’t. He has trouble with sequencing in general and this is really tough for him.
Thanks for any help. Kelly
You need some kind of concrete objects. You can go to a teacher supply store or look online; you can get sets with small cubes for ones, sticks of ten cubes, flat sheets of 100 cubes, and large cubes of 1000 small cubes. These are fairly expensive but worth the trouble.
You start first by counting out the models for any number and recognizing the ones and tens place, then the hundreds, and then the thousand. Then you review addition using the models, paying apecial attention to exchanging tens and carrying; then review subtraction with the models, paying special attention to exchanging tens and borrowing. If a child doesn’t really understand base ten, it is highly probable that he is doing carrying and borrowing by rote without understanding, so this review both teaches the concept and solidifies a necessary skill.
Then for rounding, you set up seven or eight ones cubes against a ten bar, and ask whick end you are closest to — ten or zero? The with 2 or 3, and so on. Of course five is halfway so you have to explaion the arbitrary five rounds up rule. The continue wth 342 closer to 340 or 350, and so on and so forth.