diff --git a/unit04_public_key/lab/sample_ans.md b/unit04_public_key/lab/sample_ans.md
index e215186..428734c 100644
--- a/unit04_public_key/lab/sample_ans.md
+++ b/unit04_public_key/lab/sample_ans.md
@@ -505,35 +505,38 @@ print(message.decode('utf8'))
 
 A sample run gives:
 
-<pre>
+```
 PublicKey(7044152640361902500168576401792350494310726185372977704588682647070501920385795486653093710793158373161949147824992313215786223524754692116109993477603703, 
 65537)
 PrivateKey(7044152640361902500168576401792350494310726185372977704588682647070501920385795486653093710793158373161949147824992313215786223524754692116109993477603703, 
 65537, 1031520101462581111343482730793310461173078401529280666355457029829494893917496934907266419334856470211959662572029962392609614789178286814805200163248601, 
 7009636621105341733056641551350073875772161289792261672243040042003271353299512989, 1004924081107519375914073833480034561474534624800691686376057520755477027)
 Here is my message
-</pre>
+```
+
 The keys are (e,N) for the public key, and (d,N) for the private key. In this case the value of N is:
-<pre>
+
+```
 7044152640361902500168576401792350494310726185372977704588682647070501920385795486653093710793158373161949147824992313215786223524754692116109993477603703
-</pre>
+```
+
 And e is:
-<pre>
+```
 65537
-</pre>
+```
 For the decryption key, N is the same value as the encryption key, and d is:
-<pre>
+```
 1031520101462581111343482730793310461173078401529280666355457029829494893917496934907266419334856470211959662572029962392609614789178286814805200163248601
-</pre>
+```
 The two prime numbers used (p and q) are then:
-<pre>
+```
 7009636621105341733056641551350073875772161289792261672243040042003271353299512989 1004924081107519375914073833480034561474534624800691686376057520755477027
-</pre>
+```
 Sample:
-<pre>
+```
 >>> 7009636621105341733056641551350073875772161289792261672243040042003271353299512989*1004924081107519375914073833480034561474534624800691686376057520755477027 
 7044152640361902500168576401792350494310726185372977704588682647070501920385795486653093710793158373161949147824992313215786223524754692116109993477603703L
-</pre>
+```
 
 ## E.3