A calculator

In [1] := 10 + 4
Out [1] = +14
In [2] := 3276581927324128 * 1234176413461234
Out [2] = +4043880131476789972060280853952
In [3] := Larry = 1   
Out [3] = +1
In [4] := Tom = 2
Out [4] = +2
In [5] := Randal = 3
Out [5] = +3
In [6] := Larry + Tom + Randal
Out [6] = +6
In [7] := 3 * (4 + 5)   
Out [7] = +27
In [8] := - Larry + . * (Tom ---- 23) + + + + + + Randal
Out [8] = +677
In [9] := .
Out [9] = +677
In [10] := x = (y = 3) + 4 + (z = 6)
Out [10] = +13
In [11] := y
Out [11] = +3
In [12] := z
Out [12] = +6
In [13] := x
Out [13] = +13