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.