Answer:
4
![(3)/(4)](https://img.qammunity.org/2020/formulas/mathematics/college/e902xdvhskq5go8rzqwzc0u5ermj5vc0m5.png)
Explanation:
To calculate the amount left subtract the amount used from the total amount in the tub, that is
7
- 2
![(3)/(4)](https://img.qammunity.org/2020/formulas/mathematics/college/e902xdvhskq5go8rzqwzc0u5ermj5vc0m5.png)
Change the mixed numbers to improper fractions
7
=
, 2
=
![(11)/(4)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/dqjoqagpt2l0rz8pltn0rbn750oq6syupy.png)
The subtraction can now be expressed as
-
![(11)/(4)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/dqjoqagpt2l0rz8pltn0rbn750oq6syupy.png)
=
-
← like denominators
=
= 4
![(3)/(4)](https://img.qammunity.org/2020/formulas/mathematics/college/e902xdvhskq5go8rzqwzc0u5ermj5vc0m5.png)