When you try to add 14 and 3.08 in place of the correct answer, it gives out letters and replaces some characters. How to fix?

Question

assembler

ps If you set a number and the answer is less than 10, then the answer gives normally

The code itself:

section .text
global _start

_start: 
    mov eax,'14'
    sub eax, '0'

    mov ebx, '3.08'
    sub ebx, '0'
    add eax, ebx
    add eax, '0'
    
    mov [sum], eax
    mov ecx,0
    mov edx,1
    mov ebx,1 
    mov eax,4 
    int 0x80 

    mov ecx,sum
    mov edx, 6
    mov ebx,1 
    mov eax,4 
    int 0x80 

    mov eax,1 
    int 0x80 

section .data
segment .bss
sum resb 1

Answer 1

What kind of nightmare is this, anyway? Who taught you how to convert a string to a number:

mov eax,'14'
sub eax, '0'

?
Yes, it will work for single digits, for two or more digits it will be complete nonsense ( here it is approximately written why).
Well, adding floats in the same way - you have to think of it ... You know about the existence of FPU, don't you?