diff --git a/server/src/engine/answers.test.ts b/server/src/engine/answers.test.ts
index dd2c033..5432d75 100644
--- a/server/src/engine/answers.test.ts
+++ b/server/src/engine/answers.test.ts
@@ -1,5 +1,7 @@
 import { describe, it, expect } from 'vitest'
 import { checkAnswer } from './answers.js'
+import { TEMPLATES } from './challenge-data.js'
+import { EXTRA_PROMPTS } from './challenges-extra.js'
 
 describe('checkAnswer', () => {
   // --- Tier 1: exact match after normalization ---
@@ -146,6 +148,59 @@ describe('checkAnswer', () => {
   })
 })
 
+describe('all factual prompt answers work with checkAnswer', () => {
+  // Merge extras into templates (same as challenges.ts does)
+  const templates = TEMPLATES.map(t => {
+    const extras = EXTRA_PROMPTS[t.type]
+    return extras ? { ...t, prompts: [...t.prompts, ...extras] } : t
+  })
+
+  const factualTemplates = templates.filter(t => t.scoring === 'factual')
+
+  it('every factual prompt has at least one answer', () => {
+    for (const t of factualTemplates) {
+      for (const p of t.prompts) {
+        expect(p.answers, `${t.type}: "${p.prompt}" has no answers`).toBeTruthy()
+        expect(p.answers!.length, `${t.type}: "${p.prompt}" has empty answers array`).toBeGreaterThan(0)
+      }
+    }
+  })
+
+  it('every answer self-matches with checkAnswer (case-insensitive)', () => {
+    let checked = 0
+    for (const t of factualTemplates) {
+      for (const p of t.prompts) {
+        if (!p.answers) continue
+        for (const answer of p.answers) {
+          const score = checkAnswer(answer, p.answers)
+          expect(score, `${t.type}: answer "${answer}" for "${p.prompt}" should self-match`).toBeGreaterThanOrEqual(0.75)
+          // Also test uppercase variant
+          const upper = checkAnswer(answer.toUpperCase(), p.answers)
+          expect(upper, `${t.type}: UPPER "${answer.toUpperCase()}" should match`).toBeGreaterThanOrEqual(0.75)
+          checked++
+        }
+      }
+    }
+    expect(checked).toBeGreaterThan(100)
+  })
+
+  it('MC choices always include the correct answer', () => {
+    let checked = 0
+    for (const t of factualTemplates) {
+      for (const p of t.prompts) {
+        if (!p.choices || !p.answers) continue
+        // At least one choice should match at least one answer
+        const hasCorrect = p.choices.some(choice =>
+          checkAnswer(choice, p.answers!) > 0
+        )
+        expect(hasCorrect, `${t.type}: "${p.prompt}" choices ${JSON.stringify(p.choices)} don't include correct answer ${JSON.stringify(p.answers)}`).toBe(true)
+        checked++
+      }
+    }
+    expect(checked).toBeGreaterThan(50)
+  })
+})
+
 describe('checkAnswer performance', () => {
   it('completes 1000 checks in under 50ms (<0.05ms each)', () => {
     const answers = ['Paris', 'London', 'Tokyo']
diff --git a/server/src/engine/challenges-extra.ts b/server/src/engine/challenges-extra.ts
index f650801..73be0b8 100644
--- a/server/src/engine/challenges-extra.ts
+++ b/server/src/engine/challenges-extra.ts
@@ -139,7 +139,7 @@ export const EXTRA_PROMPTS: Record<string, PromptEntry[]> = {
     { prompt: 'How many zeros trailing 100! (100 factorial)?', answers: ['24'], choices: ['20', '22', '24', '25'] },
     { prompt: 'What is the volume of a sphere with radius 3? (use π≈3.14)', answers: ['113.04', '113.1'], choices: ['84.78', '113.04', '150.72', '36'] },
     { prompt: 'What is 0o777 in decimal?', answers: ['511'], choices: ['255', '511', '777', '999'] },
-    { prompt: 'If hash rate is 400 EH/s, how many hashes per second is that?', answers: ['4e20', '400000000000000000000'], choices: ['4×10^17', '4×10^18', '4×10^20', '4×10^22'] },
+    { prompt: 'If hash rate is 400 EH/s, how many hashes per second is that?', answers: ['4e20', '400000000000000000000', '4×10^20', '4*10^20'], choices: ['4×10^17', '4×10^18', '4×10^20', '4×10^22'] },
     { prompt: 'What is the derivative of x³?', answers: ['3x²', '3x^2'], choices: ['x²', '2x³', '3x²', '3x'] },
     { prompt: 'What is sin(90°)?', answers: ['1'], choices: ['0', '0.5', '1', '-1'] },
     { prompt: 'How many unique secp256k1 private keys exist (approximately)?', answers: ['2^256', '1.16e77'], choices: ['2^128', '2^256', '2^512', '2^64'] },
@@ -428,7 +428,7 @@ export const EXTRA_PROMPTS: Record<string, PromptEntry[]> = {
     { prompt: 'What is a CVE?', answers: ['common vulnerabilities and exposures'], choices: ['Common Vulnerabilities and Exposures', 'Computer Virus Encyclopedia', 'Certified Vulnerability Expert', 'Core Validation Engine'] },
     { prompt: 'What is the purpose of a firewall?', answers: ['filter network traffic', 'block unauthorized access'], choices: ['Filter network traffic', 'Speed up internet', 'Store passwords', 'Encrypt files'] },
     { prompt: 'What tool is commonly used for penetration testing?', answers: ['metasploit', 'nmap', 'burp suite', 'kali'], choices: ['Metasploit', 'Microsoft Word', 'Photoshop', 'Notepad'] },
-    { prompt: 'What is phishing?', answers: ['fake emails to steal information', 'fraudulent communication'], choices: ['Fake communications to steal data', 'Fishing for data on the dark web', 'A type of malware', 'Hacking via phone'] },
+    { prompt: 'What is phishing?', answers: ['fake communications to steal data', 'fake emails to steal information', 'fraudulent communication'], choices: ['Fake communications to steal data', 'Fishing for data on the dark web', 'A type of malware', 'Hacking via phone'] },
     { prompt: 'What does HTTPS use for encryption?', answers: ['tls', 'ssl', 'ssl/tls'], choices: ['TLS/SSL', 'AES only', 'RSA only', 'PGP'] },
     { prompt: 'What is a rootkit?', answers: ['malware that hides in the os', 'hidden malware', 'stealthy malware'], choices: ['Malware that hides deep in the OS', 'A Linux admin tool', 'A password manager', 'A type of firewall'] },
     { prompt: 'What hash algorithm is considered broken for security?', answers: ['md5', 'sha1', 'sha-1'], choices: ['MD5/SHA-1', 'SHA-256', 'bcrypt', 'Argon2'] },