bash script sum

Bash script exercise.
Add variable to the result of the sum.  E.g.
1 1 2 3 5 8 13 21, etc.


#!/bin/bash
x=1
y=1
ans=0

while [ $ans -lt 100 ]
#while true
do
  ans=$(( x + y ))
  echo $x + $y = $ans
  x=$y
  y=$ans
done