To estimate this, let's consider the following factors:

Smartphone Users:

InMobi is a global mobile advertising platform. So, we would need an estimate of the global smartphone users. As of 2021, there were approximately 3.8 billion smartphone users worldwide.

Average Time Spent: 

Let's say on average, a person spends 3 hours a day on their smartphone browsing apps, games, or websites where they could potentially see an InMobi ad.

Ad Frequency: 

It's challenging to determine how often ads appear, as this can vary greatly. For our calculation, let's assume a user sees an ad every 5 minutes. That's 12 ads per hour.

Market Share: 

InMobi is a major player in the global mobile advertising space, but they don't serve all ads. Let's assume they have a 10% market share.

Therefore, the number of daily ad impressions would be approximately:3.8 billion (smartphone users) * 3 hours/day * 12 ads/hour * 10% (market share) = 13.68 billion ad impressions daily.