There was a student had a noun and it was 1st declension:

-a, -ae, -ae, -am, -a

-a, -ae, -ae, -am, -a

-a, -ae, -ae, -am, -a

...the 1st declension endings!

There was a student had a noun and it was 2nd masc'lin:

-us, -i, -o, -um, -o

-us, -i, -o, -um, -o

-us, -i, -o, -um, -o

...the 2nd masc'lin endings!

There was a student had a noun and it was 2nd neuter:

-um, -i, -o, -um, -o

-um, -i, -o, -um, -o

-um, -i, -o, -um, -o

 ...the 2nd neuter endings!

There was a student had a noun and it was 3rd declension:

blank, -is, -i, -em, e

blank, -is, -i, -em, e

blank, -is, -i, -em, e

...the 3rd declension endings!