Given that each rectangle has 4 boxes inside, then we have to write a 4 in the denominator.
The first rectangle has 4 boxes shaded, then we have to write a 4 in the numerator, getting 4/4, which is equal to 1.
The second rectangle has 3 boxes shaded, then we have to wite a 3 in the numerator, getting 3/4.
Therefore, in mixed numbers the two rectangles represent :
And, as an improper fraction, we need to add the shaded boxes, which is 4 + 3 = 7, and then divide by 4, like before, getting 7/4