'how often' vs 'how much' vs 'many often' vs 'how many'

[Huda2]

hi,

I am familiar with that product. I don't know _____ times I've seen it advertised on TV.

how many
how often
how much
many often

why how many is best , what about how often?

[Daemon99]

I am familiar with that product. I don't know how many times I've seen it advertised on TV.

I am familiar with that product. I don't know how often I've seen it advertised on TV.

Don't use times when you are using often.
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Non-native speaker of English
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I intend to live forever - so far, so good.

[Huda2]

thanks