$a=3;
 $b="x";
 $c=4;
 $a*=3;     #$a=$a*3; $a now equal to 9;
 $a/=3;     #$a=$a/3; $a (9) divided by three which equals 3;
 $a+=2;     #$a=$a+2; $a is now equal to 5;
 $a-=2;     #$a=$a/2; $a is now equal to 3;
 $b x=3;    #$b=$b x $3 $b is now equal to "xxx";
 $b .="33"; #b=$b."33"  $b is now equal to "xxx33";
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