Math - Making 100

This week we are working on making 100. The students are going to accomplish this by using a Base-10 Flat. A Base-10 Flat is a 10 by 10 block grid on paper. Much like this:

The problem will give the student the whole (100) and a part. The student will find the other part by using the Base-10 Flat. So, Part + Part = Whole.

Example:
The whole is 100 and one part is 59. We need to find the second part. This problem can be shown in a basic math equation like these: 59 + ? = 100 or 100 - 59 =?

First, on our Base-10 Flat paper, we need to fill in 59 squares out of the 100 total squares. To do this, the students have been taught that one row in a Base-10 Flat has 10 squares. So, to fill in 59 squares quickly, all you have to do is shade in 5 complete rows and 9 individual squares to make 59. It is preferred to shade the rows vertically (up and down), beginning on the left side.

Next, to find the number of squares remaining, count the rows starting from the right and individual squares that are not shaded. Counting each individual square is tedious and time-consuming, that's why it is so important for the students to understand the relationship of one row equals 10 squares.

Now, we can see that the remaining part is 41.