These three numbers: a single digit can have four numbers (0, 3, 8, 7) to choose from, a decimal digit can also have four numbers (0, 3, 8, 7) to choose from, and a hundred digit can only have three numbers (3, 8, 7) to choose from, so these numbers can form three numbers: 4 * 4 * 3.

300、303、307、308;

330、333、337、338;

370、373、377、378;

380、383、387、388;

700、703、707、708;

730、733、737、738;

770、773、777、778;

780、783、787、788;

800、803、807、808;

830、833、837、838;

870、873、877、878;

880、883、887、888。

This is a simple mathematical arrangement problem.