From what I can find it is the objects used to teach counting ,grouping,addition,subtraction. They are block,rods,and squares. Www.delta-education.com/productgallery.aspx?subID=110&menuID=113

They are blocks used to aid in identifying the value of a number.

There are single blocks for counting ones and a stick of blocks which contains 10 individual blocks and there is a block which contains 10 sticks and this represents 100. So to learn the value of the number 83 you would need 8 ten sticks and 3 ones blocks. To discover the value of 456 you would need 4 100 blocks, 5 tens sticks and 6 ones. There is also a cube which contains 100 tens sticks or 10 100 blocks to represent 1000. These are very helpful when students are learning to borrow in subtraction. They need to understand if you need to do this problem 75 - 69 = you need to borrow a ten from the 7 or 7 tens to give it to the 5 to make 15 ones so you can subtract the 9 in the ones place. Now you have 6 tens 15 ones and you will subtract 6 tens and 9 ones. Your answer will be 6 ones.

There are single blocks for counting ones and a stick of blocks which contains 10 individual blocks and there is a block which contains 10 sticks and this represents 100. So to learn the value of the number 83 you would need 8 ten sticks and 3 ones blocks. To discover the value of 456 you would need 4 100 blocks, 5 tens sticks and 6 ones. There is also a cube which contains 100 tens sticks or 10 100 blocks to represent 1000. These are very helpful when students are learning to borrow in subtraction. They need to understand if you need to do this problem 75 - 69 = you need to borrow a ten from the 7 or 7 tens to give it to the 5 to make 15 ones so you can subtract the 9 in the ones place. Now you have 6 tens 15 ones and you will subtract 6 tens and 9 ones. Your answer will be 6 ones.

Base TenBase-Ten Blocks is a teaching tool to help your child learn decimal points, multiplication, and more. You can look up how to use this system by clicking my link.