Several parts combine into one character.

考 is etymologically a sibling of 老 (old / aged) — both characters originated from the same pictograph of an elderly person leaning on a staff. As the writing system matured, the original concept split into three related characters that share a deep family resemblance: 老 (old / aged), 孝 (filial piety — what one owes the elderly), and 考 (to ponder deeply / to test). The conceptual link is profound: deep reflection is what years of accumulated experience produce. The character preserves the East Asian wisdom that genuine consideration requires the patience and depth that only age confers.

Korean reading "go." 考慮 (goryeo, consideration / careful thought), 參考 (chamgo, reference / consultation), 思考 (sago, thinking — used in 사고력 sagoryeok "thinking ability"), 考察 (gochal, examination / study), 考試 (gosi, civil service exam — also the major Korean professional examination system: 사법고시 司法考試 was the legal-profession entrance exam, and the term 고시 still resonates with social aspiration), 模擬考査 (mogi gosa, mock test — used in Korean educational system).

Mandarin kǎo, 3rd tone. 考 (kǎo, to test / examine / ponder), 考试 (kǎoshì, exam — central to every Chinese student's life), 参考 (cānkǎo, to consult / refer to), 思考 (sīkǎo, deep thinking), 考虑 (kǎolǜ, to consider — used in 让我考虑一下 "let me consider it"), 高考 (gāokǎo, "high test" = the Chinese national college entrance exam — perhaps the most consequential single examination in the world, taken annually by ~10 million Chinese high schoolers and determining university placement).

Japanese on-reading コウ (kō) — 思考 (shikō, thinking / cognition), 参考 (sankō, reference), 考察 (kōsatsu, examination / inquiry), 考案 (kōan, contrivance / invention — also the Buddhist 公案 kōan but with different kanji). Kun-reading かんがえる (kangaeru, "to think / consider") — 考える is one of the most fundamental verbs of mental activity in Japanese: 考えてみる (kangaete miru, "let me think about it"), よく考える (yoku kangaeru, "to think carefully"), 考え方 (kangaekata, "way of thinking / mindset"). The verb appears constantly in Japanese reflective speech.

Memory aid: family with 老 (old) and 孝 (filial piety) — the elderly person bent over time = the depth of pondering.