百分之…grammar point · tier 2 · percentages 百分之 N (N parts in a hundred)
States a percentage: 百分之 holds the hundred fixed as the base, and the number after 之 says how many of those hundred parts are meant — 百分之五 = five percent.
You want to give a proportion against a fixed base of a hundred.
序 · The move
1Lay down 百分之 — the hundred as the unchanging base.Is the base a hundred? If it is a different base, the front number changes (三分之 = out of three).
2Put the count of parts right after 之.Is the part-count on the right of 之, and the whole on the left?
3Attach it to a noun with 的 if it modifies one: 百分之五的人.Does 的 sit between the percentage and the noun?
例 · Examples
1這裡只only有百分之classical of — points to the parts五five percent — five parts in a hundred的attaches the percentage to 人人沒出過國have never been abroad。
Here only five percent of people have never been abroad.
界 · Boundary
分之 fractions (三分之一)
The number before 分之 is the base, the number after 之 is the count taken. 百分之五 fixes the base at a hundred (5%); 三分之一 fixes it at three (one third). Percentage is the special case where the base is locked to a hundred; a fraction lets any number sit in front.
成 counts in tenths and drops 分之 (八成 = eighty percent, eight parts in ten); 百分之 counts in hundredths and keeps the full 分之 (百分之八十). 成 for the round tenth, 百分之 for the exact hundredth.
✗ 五百分之 → ✓ 百分之五 (the base 百 leads, the part-count follows 之)
✗ 百分五 → ✓ 百分之五 (之 is required between the base and the count)
✗ 百分之五人 → ✓ 百分之五的人 (的 joins the percentage to the noun)
English appends a sign or word after the number (5%, five percent), so learners say the number first and reach past 之; Chinese sets the base 百分之 in front and the count after it, the reverse word order.