I believe that math students of all ages learn abstract notions by first experiencing them concretely with shapes they can actually see, touch and manipulate **{visual model}**. we will use of concrete teaching aids such as** base-ten blocks** help provide insight into the creation of the standard algorithm for addition. In this blog, we will use them to find the sum of two **whole numbers**, 29 and 47 **(A)**. I will be using two types of blocks **(B)**. A green square block has a value of 1 unit, and a blue rod has a value of 10 units. I represent the values of the two **addends** using these two blocks. I make sure that they are grouped in the appropriate columns according to the structure of the **decimal number system** (See “Decimals”). I then add all the blue rods together in the tens column, and add all the green squares together in the ones column **(C)**. Notice that we have more than ten green squares. I group ten of these squares together **(D)** and replace them with a blue rod **(E)**. This blue rod gets moved from the ones column to the tens column **(F)**. Now we have seven blue rods and six green squares, which represent the **sum**: 76 **(G)**.

We can use these two blocks to visually add numbers 1-99. Additional blocks can be added that represent larger multiples of 10 so that larger whole numbers can be used.