WHOLE CHARACTER
第
prefix for ordinal numbers; rank; order
第 forms ordinal numbers such as 第一 and 第二; it can also mean rank or mansion in formal words.
Modern 第 has bamboo above a shortened 弟-form. The shortened lower geometry is not represented by drawing a complete independent 弟, so this page teaches the whole character. 答/等 use the real ⺮ bamboo-top variant.