Yes, of course!
Ricardo has made 4 out of the 12 recipes in his cookbook.
To find out what fraction of the recipes he has made, you can write it as a fraction:
4/12
To simplify this fraction, you can divide both the numerator and denominator by 4, which gives:
4/12 = 1/3
Therefore, Ricardo has made 1/3 of the recipes in his cookbook.