DB<4> $num2 ="19.90"

 DB<5> printf "%.20f", $num2*100
1989.99999999999980000000
 DB<6> p 1990 == $num2 *100

 DB<7> p 1990 eq $num2 *100
1
  DB<8> say ">". $num2 *100 ."<"
>1990<

 DB<9>