I need to convert a number to binary. I know that I can take a number and write it to output (in dos) as binary but don't know how to assign that binary number to a variable.

Can someone point me in the right direction?

Code:
INCLUDE Irvine32.inc

CR = 0Dh ;carriage return

LF = 0Ah ;line feed

.data
	myMessage1 BYTE "        Welcome to MyProgram that Multiplies a number",0
	myMessage2 BYTE "       from the keyboard by 26 using the binary Left Shift in Assembler",0
	enterHex BYTE " Please enter a number in hex and I will multiply it by decimal 26: ", 0	
	binMessage BYTE "     The binary number is: ", 0
	hexMessage BYTE "     The hexidemcial number is: ", 0
	decMessage BYTE "     The decimal number is: ", 0	
	num DWORD 0
	
	testMessage BYTE " Please enter your age in hex: ", 0
	
.code
main PROC

 	mov edx,OFFSET myMessage1	; store welcome message address in edx.Use edx register 		
	call WriteString		; Print welcome message
	call Crlf			; new line
	call Crlf			; new line
	
	mov edx,OFFSET myMessage2	; store welcome message address in edx.Use edx register 		
	call WriteString		; Print welcome message
	call Crlf			; new line
	call Crlf			; new line
	call Crlf			; new line
	
	mov edx,OFFSET enterHex		; moves whats in the enterHex to edx
	call WriteString		; prints what is in the edx
	call ReadHex			; reads a hexadecimal integer from the input
	call Crlf			; new line
	call Crlf			; new line	

	mov num,OFFSET enterHex

;MUST CONVERT NUMBER TO BINARY HERE

	mov eax,num			; moves number entered into eax
	mov ebx,num			; moves number entered into ebx
	mov ecx,num			; moves number entered into ecx
	shl eax,4			; shifts left 2 power of 4
	shl ebx,3			; shifts left 2 power of 3
	add eax,ebx			; addes ebx to eax
	shl ecx,1			; shifts left 2 power of 1
	add eax,ecx			; adds ecx to eax
	
	call DumpRegs			; Dump the registers	
	call Crlf			; new line
	call Crlf			; new line
	
	mov edx,OFFSET binMessage 	; moves whats in printBin to edx
	call WriteString		; prints the info stating the number in binary
	mov edx, eax
	call WriteBin			; prints the number in binary
	call Crlf			; new line
	call Crlf			; new line
	
	mov edx,OFFSET hexMessage 	; moves whats in printBin to edx
	call WriteString		; prints the info stating the number in binary
	mov edx, eax
	call WriteHex			; prints the number in binary
	call Crlf			; new line
	call Crlf			; new line
	
	mov edx,OFFSET decMessage 	; moves whats in printBin to edx
	call WriteString		; prints the info stating the number in binary
	mov edx, eax
	call WriteDec			; prints the number in binary
	call Crlf			; new line
	call Crlf			; new line	
		
	call WaitMsg
	exit
main ENDP
END main