I Chronicles 25:17 Midrash

הָעֲשִׂירִ֣י שִׁמְעִ֔י בָּנָ֥יו וְאֶחָ֖יו שְׁנֵ֥ים עָשָֽׂר׃

The tenth to Shimei, his sons and his brethren, twelve;

Read midrashic interpretation of I Chronicles 25:17: and classical rabbinic exegesis.