Test 1. Addition of rational numbers

 1. Express each of the following as a single fraction:

 2. Express each of the following as a single fraction:

 3. Express each of the following as a single fraction:

 4. Express each of the following as a single fraction:

 5. Express each of the following as a single fraction:

 6. Express each of the following as a single fraction:

 7. Express each of the following as a single fraction:

 8. Express each of the following as a single fraction:

 9. Express each of the following as a single fraction:

10. Express each of the following as a single fraction:

11. Express each of the following as a single fraction:

 а)  ху;      b)  х + у;     
 c)  2;       d)  4.

12. Express each of the following as a single fraction: