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

This is the algebraic expression for this model
Using subtraction property of equality
Then, we get

After simplification, we get

Hence, the unknown number=144