Answer :
For the first equation, we recall the commutative property of addition.
[tex]\begin{gathered} 3\text{ }\frac{1}{4}+1\text{ }\frac{4}{9}=\text{ }4\text{ }\frac{25}{36}\text{ and 1 }\frac{4}{9}+3\frac{1}{4}=4\text{ }\frac{25}{36} \\ \\ \end{gathered}[/tex]are equivalent.
For the second equation, we recall the commutative property of addition.
[tex]2\text{ }\frac{1}{3}+1\text{ }\frac{3}{4}=4\frac{1}{12}and\text{1}\frac{3}{4}+2\frac{1}{3}=4\frac{1}{12}[/tex]are equivalent.
For the third equation, we recall the commutative property of multiplication.
[tex]3\frac{1}{4}\cdot1\frac{4}{9}=4\text{ }\frac{25}{36}\text{ and 1 }\frac{4}{9}\cdot3\frac{1}{4}=4\frac{25}{36}[/tex]are equivalent.
Finally, for the last equation, we recall the commutative property of multiplication.
[tex]2\frac{1}{3}\cdot1\frac{3}{4}=4\frac{1}{12}\text{ and }1\frac{3}{4}\cdot2\frac{1}{3}=4\frac{1}{12}[/tex]are equivalent.