[code]a:=1/2[/code] --- Assignment of variable[br][br][code]Delete[a][/code] --- Deletion of variable[br][br]x+y=1 --- Assignment of equation[br]LeftSide[x+y=1] -> x+y[br]RightSide[x+y=1] -> 1[br][br][code]#[/code] --- Copies the previous output.[br][code]#2[/code] --- Copies the output of row 2.[br][code]$[/code] --- Inserts a reference to the previous output.[br][code]$2[/code] --- nserts a reference to the output of row 2.