Is saying had twice correct grammar?

No, "had twice" is not grammatically correct in most cases.

"Had" is the past participle of "have." You can use "had" to form the past perfect tense, or to show possession in the past.

"Twice" means "two times."

Here's how you would typically use "had" and "twice" in a sentence:

* "I had twice as much money as you." (This means you had double the amount of money.)

Here are some examples of how to use "had" and "twice" correctly:

* I had twice the amount of homework yesterday.

* She had twice as many cookies as he did.

* They had twice the fun at the party last year.

Let me know if you have any other grammar questions!