Should I choose "increasingly" or "increasing"?

Question

An increasingly/increasing large number of people are using online travel sites rather than travel agents.

Increasingly is a adverb , increasing is adjective.

So Which should I choose?

Answer 1

Increasingly is a adverb , increasing is adjective.

Adverbs modify verbs or other modifiers.

Adjectives modify nouns.

So you have to figure out what increasing[ly] is modifying.

An increasingly/increasing large number of people are using online travel sites rather than travel agents.

Large is a modifier that is modifying people - and we are saying that it's getting larger and larger over time. The largeness is increasing.

So increasingly - the adverb is used.

Answer 2

Since the word increasing is modifying the words "large number", which is a noun, the correct word is increasing.

Answer 3

EITHER

An increasingly large number of people...

OR

An increasing number of people....

The second is more economical, but some people might think that the longer form adds emphasis.