We can start off by making 12 1/2 to an improper fraction:
12 1/2 = 25/2
Divide the large jar of salsa by the small jar of salsa: 75 / 25/2.
Reciprocal of second and turn divide to multiply:
75 * 2/25.
150/25 = 6.
So 6 jars of small salsa = 1 large jar of salsa.