past habits

[Solan]

We use " used to " or " would" to express past habits.

My question is about the negative form of "would".
Can I use " would not" for the negative form, or I must change it to " didn't use to" ?
"Wouldn't" expresses refusing something?? or it can be negative form of past habits tense?

When I was a child I would practice mathematics every day.
When I was a child I wouldn't practice mathematics every day.

[Beeesneees]

That form is fine.
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Cheers m' dears!