Here is a great web application that shows what it means to add numbers using regrouping. The program requires JAVA to be loaded on your computer to view and use it.
The program is a fun, interactive way to understand the meaning of regrouping in addition. Follow the instructions below to use the program. It will seem a little tough at first, but after playing with the application for a while you will start to "see" the reasoning behind the concept of regrouping. Move the base-10 blocks to help solve the problems.
First, start by choosing the number of columns (place values) that you want. Do this by clicking on the up/down arrows in the bottom right hand corner.
Next, you will see a number sentence appear on the right hand side of the screen. You will also see base-10 blocks representing both numbers in the problem in the middle of the screen.
The idea behind regrouping is that you can't have a number larger than 9 in any column (place value).
Next, begin adding blocks of the same kind, starting with the ONES place value. You will see two sections separated by a dotted line for each column (place value). If you have more than 9 in both sections combined, you need to drag some of the small blocks from one section into the other section to make 10.
(It does not matter whether you drag blocks from the top to the bottom or vice versa. Just make sure that you end up with 10 blocks in one side of the column.)
Once you have 10 blocks of one kind in one section of the column you need to
"regroup". You regroup by right-clicking in the column and dragging around the blocks to form a rectangle around them.
Make sure to drag the rectangle around all the blocks for the
"regrouping" to work. You should see the blocks come together and form the next kind of block (TENS) for the next column (place value) to the left. You will also see the number sentence on the right change to show you what is happening in the math problem.
After you have regrouped in the ONES, continue the process for the TENS and HUNDREDS if necessary. The virtual manipulation of the blocks really helps to show what is actually happening when regrouping is taking place. Play around with the program and soon you'll be a regrouping wiz!!
Click on the link below to take you to the website.
