diff --git a/_posts/2024-10-30-coa-three.md b/_posts/2024-10-30-coa-three.md
index 98dc678d657c..00d98b5dd9ec 100644
--- a/_posts/2024-10-30-coa-three.md
+++ b/_posts/2024-10-30-coa-three.md
@@ -122,15 +122,17 @@ LOAD A <-> AC <- A
 
 ### 0-address instructions
 
-Use a stack to find the operands. See the example of c=a+b below:
+Use a stack to find the operands. See the example of c=a-b below:
 
-```
+```asm
 push a
 push b
-add // pop a and b from stack and add them, push the result to stack
+sub  ; pop a and b from stack and add them, push the result to stack
 pop c
 ```
 
+The operation command find the operands from the top of the stack. And the first operand is below the second operand.
+
 ## Instruction set design
 
 ## Reverse Polish Notes
@@ -147,6 +149,81 @@ pop c
 
 **Answer:**
 
+- For zero address instructions:
+
+```asm
+PUSH B
+PUSH C
+MUL
+PUSH A
+ADD
+PUSH D
+PUSH E
+PUSH F
+MUL
+SUB
+DIV
+```
+
+- For one address instructions:
+
+```asm
+LOAD B       ; Load B into register
+MUL C
+
+STORE TEMP1  ; Store the result of multiplication in TEMP1 register
+
+LOAD A
+ADD TEMP1
+
+STORE TEMP2
+
+LOAD E
+MUL F
+
+STORE TEMP3
+
+LOAD D
+SUB TEMP3
+
+STORE TEMP4
+
+LOAD TEMP2
+DIV TEMP4
+
+STORE RESULT
+```
+
+- For two address instructions:
+
+```asm
+MOVE R1, B       ; Load B into reg R1
+MUL R1, C       ; R1 = B * C
+
+MOV R2, A       ; Load A into reg R2
+ADD R2, R1      ; R2 = A + (B * C)
+
+MOVE R3, E
+MUL R3, F       ; R3 = E * F
+
+MOVE R4, D
+SUB R4, R3      ; R4 = D - (E * F)
+
+DIV R2, R4      ; R2 = (A + B * C) / (D - E * F)
+
+MOVE RESULT, R2
+```
+
+- For three address instructions:
+
+```asm
+MUL R1, B, C       ; R1 = B * C
+ADD R2, A, R1      ; R2 = A + (B * C)
+MUL R3, E, F       ; R3 = E * F
+SUB R4, D, R3      ; R4 = D - (E * F)
+DIV RESULT, R2, R4 ; RESULT = (A + B * C) / (D - E * F)
+```
+
 **Question 12.18:**
 <br/>
 ![Question 12.18 ](/assets/img/COA-images/homework/12-18.png){: .mx-auto.d-block :}