计
jì · HSK 7
to calculate
🧮 计 = 讠speech radical + 十 ten; counting out loud by tens = calculate
The 讠 on the left is the speech radical (compressed 言, words); the 十 on the right is the number ten. Words plus ten points to reckoning aloud: to count, calculate, compute. Also a surname, Ji.
计 — speech radical 讠 (言) + ten 十
计 is a semantic compound: 言 'speech/words' plus 十 'ten', suggesting counting or reckoning aloud. The original sense was to calculate or tally numbers, which extended to 'plan, scheme, plot' — any kind of mental reckoning. Modern uses like 计算 (calculate) and 计划 (plan) preserve both threads.