I am a student and need help learning assembly language. I simply want to print out 3 the values that I entered to the console. The goal of the program is to get 3 positive integers, A, B and C, in descending order from the console. When I run the program and enter 20 for the first value, 10 for the second value, and 5 for the third value, the expectation is that those values will each be printed out. However, 20 is the only value that seems to be printed out.

I expected to see 20105 but instead I saw 202020.
Here is the current code:

.data
  promptFirstNum  BYTE "First number: ", 0
  promptSecondNum BYTE "Second number: ", 0
  promptThirdNum  BYTE "Third number: ", 0

  ; Declare all of the values for what the user will enter
  valueA  DWORD ?
  valueB  DWORD ?
  valueC  DWORD ?

.code
main PROC
  ; Ask for first number and set it to valueA
  MOV   EDX, OFFSET promptFirstNum
  call  WriteString
  call  ReadDec
  MOV   valueA, EAX

  ; Ask for second number and set it to valueB
  MOV   EDX, OFFSET promptSecondNum
  call  WriteString
  call  ReadDec
  MOV   valueB, EBX

  ; Ask for third number and set it to valueC
  MOV   EDX, OFFSET promptThirdNum
  call  WriteString
  call  ReadDec
  MOV   valueC, ECX
  call  CrLf
  call  CrLf

  ; This section will be for testing, it should pring out 20105 if it works correctly
  MOV   EAX, valueA
  call  WriteDec
  MOV   EBX, valueB
  call  WriteDec
  MOV   ECX, valueC
  call  WriteDec
  call  CrLf

Invoke ExitProcess,0; exit to operating system
main ENDP
END main.data