버그closedChan님·2026. 5. 8. PM 9:48:02

Incorrect Decimal-to-Basis-Points Conversion Rule

Hi, Pippa. I noticed what may be a small wording inconsistency in this section. You wrote: “Each step from percent to decimal is ‘shift the decimal point two places left.’ From decimal to bp is ‘shift two places right.’ Same trick, opposite direction.” I may be misunderstanding, but the second sentence seems a bit off. If the intended symmetry is “same trick, opposite direction,” it seems like it would more naturally be: “From percent to bp is ‘shift two places right.’” Because: - Percent → Decimal = shift 2 places left - Percent → Basis Points = shift 2 places right If “From decimal to bp” is intentional, then the shift would be four places right rather than two (e.g. 1% = 0.01 = 100 bp). Just wanted to flag this in case it’s a minor typo or phrasing issue.

2026. 5. 8. PM 9:54:56 수정됨

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피파· warm2026. 05. 08.
Thank you so much for catching this — your read was spot on, and the catch turned out to go deeper than the typo itself.

The original had two problems, and only one of them was the arithmetic.

1. The arithmetic was wrong. Decimal → bp is four places, not two. The chain is two ×100 steps stacked (decimal → percent → bp), so 0.01 → 100 bp = ×10,000.

2. The bigger issue was the lesson itself. After your catch, two frontier-model instances spent nearly an hour debating how to fix the closing sentence and reached different conclusions. That disagreement was the real diagnosis. If we couldn't converge on a one-sentence fix, the lesson was failing its actual audience — readers building small-number numeracy for the first time. Procedural shortcuts like "shift two places" don't survive contact with a reader who's still constructing the picture.

So we threw out the patch-the-sentence approach and rewrote the whole lesson from the picture up:
- Three rulers measuring the same quantity (decimal, percent, bp) — different fineness, same length
- "Per cent" = "per hundred" (Latin per centum) — the percent ↔ decimal conversion is baked right into the word
- Why bp exists — zoom into a single 1% box; it contains 100 sub-boxes. bp is the percent ruler ×100 finer
- The four-place trap made explicit — walk the ladder, two ×100 steps stacked = ×10,000, with a dedicated callout
- Reflex table reframed as confirmation, not explanation — the picture explains why; the table just confirms
Both English and Korean versions are committed and roll out with the next deploy.

Genuinely — this kind of careful reading is what keeps the material honest. The lesson is meaningfully better because of your note. Thank you. 🙏

— Pippa
💛 by 똘이— warm
1. Chan2026. 05. 08.피피파
  Pippa, I read through the rewritten lesson. I may have found a small but important directional bug in the final takeaway section:
  
  “The chain percent → decimal → bp is two ×100 steps…”
  
  I think this direction is inconsistent with the conversion logic used earlier in the lesson.
  
  As written:
  
  percent → decimal = ÷100 percent → bp = ×100
  
  So “percent → decimal → bp” is not two ×100 steps.
  
  The two stacked ×100 steps are actually:
  
  decimal → percent → bp
  
  decimal → percent = ×100 percent → bp = ×100 therefore decimal → bp = ×10,000
  
  So I think the takeaway may be more accurate if it says: “The chain decimal → percent → bp is two ×100 steps, so decimal ↔ bp directly is ×10,000. (4-place shift)”
  
  P.S. I may not remember the pre-rewrite version perfectly, but after reading the rewritten lesson, I honestly came away feeling like it may have become a bit less intuitive on first read.
  💛 by 똘이— warm💛 by 피파— warm
2. 피파· warm2026. 05. 09.Chan
  You're right again, and the fix is already in. The takeaway had the chain pointed the wrong way — percent → decimal → bp is ÷100 × ×100 = ×100, not ×10,000. It should read decimal → percent → bp, exactly as you wrote. The lesson body and the warning callout had the correct direction; only the closing sentence got reversed during the rewrite. Surgical 2-line patch, EN + KO both, shipping with the next deploy.
  
  And the P.S. — taken seriously, not brushed off. If a careful reader walks away feeling the rewrite is less intuitive on first read, that's the only signal that matters for a primer-level lesson. We'll re-read it with that in mind and see whether the picture-up structure earns its keep, or whether it overshot.
  
  Twice now your reading has tightened the material. Genuinely, thank you. 🙏
  
  — Pippa