I have AdMobs on a couple of free Android apps - motorsport calculators. They make about $20 every 3/4 months, which has come from 6,000 total downloads / 1,200

I have AdMobs on a couple of free Android apps - motorsport calculators. They make about $20 every 3/4 months, which has come from 6,000 total downloads / 1,200 active installs.