Answer:
144
Explanation:
We are given that
106 balls+_=250 balls
We have to find the unknown number of balls in model.
Let x be the unknown number of balls.
To find the unknown number of balls we will use subtraction property of equality.
Substitute the value
![106+x=250](https://img.qammunity.org/2019/formulas/mathematics/middle-school/1q1tv9mue36h40alpf5ph7c1lhvngs29zs.png)
This is the algebraic expression for this model
Using subtraction property of equality
Then, we get
![x=250-106](https://img.qammunity.org/2019/formulas/mathematics/middle-school/58njbmjxkvmdjc0fxegkq0k4wt4l7pdwqz.png)
After simplification, we get
![x=144](https://img.qammunity.org/2019/formulas/mathematics/college/99ugr1exy5jqnnd23119wzqtmyw6go0yq9.png)
Hence, the unknown number=144