Identify the gerund and classify whether it is used as a subject, direct object, indirect object, predicate noun, appositive, and object preposition.
1. He left without saying goodbye.
2. Studying is investing for the future.
3. Making a major decision is no easy thing.
4.Monty tried mending the cup back together.
5. You may start rearranging the facts to suit your needs.
6. She makes a good living.
Gerunds are verb forms ending in -ing and acting as nouns in a sentence.
http://www.chompchomp.com/terms/gerund.htm
In #1, 'saying' is the gerund and it's serving as the object of the preposition 'without.'
Study the webpage I've given you, and let us know what you think about the others.