7238 (the numbers rotate positions one place to the right)

A mirror.

The match!

Of course, adding seven to five makes twelve and not thirteen.

Stone.

27

In the first row divide both numbers by 7 to obtain the digits in the brackets; in the second row divide by 8, and obtain the digits in the brackets. In last row divide by 9, and obtain the digits in the brackets.
27 / 9 = 3

A pupil

Fill up the 3 gallon container first. Pour it into the five gallon container. Fill up the 3 gallon container again, and fill up the rest of the 5 gallon container, and you should have 1 gallon left over in the 3 gallon container.

Yesterday

7.5º
Clock has 360º and 12 hours: 360º/12 =30º
The angle between hour and hour is 30º
15 minutes = 1/4 of hour
At the 3:15, 30º/4=7.5º

Grandfather or Grandmother.

S is daughter of P and sister of T. So, T is daughter of P.

Now, the sister of P is the daughter of M. This means that P is also the daughter of M. Clearly, T is the granddaughter of M.
So, M is the Grandfather or Grandmother of T.

The one way they are similar is that they are in the same instrument family and three ways they're different are they don't have the same amount of strings, the bass has a deeper sound, and bass is bigger.