Convert the following infix expressions into equivalent postfix expressions:

x * (y + z) - (w + t)

(x + y) / (z - w) * t

((x - y) + (z - w) / t) * u

x - y / (z + w) * t / u + (v - s)

A+B-C

(A+B)*C

(A+B)*(C_D)

(A+((B+C)*(E-F)-G)/(H-I)

A+B*(C+D)-E/F+G+H

Convert the following postfix expressions into equivalent infix expressions (remember, order of operands can't change):

x y + z * w -

x y * z / w +

x y z + * w -

Evaluate the following postfix expressions (meaning, computing it to a single number):

17 5 3 - * 6 + =

14 2 * 8 + 6 / 5 + =

15 16 3 10 2 + + - + 8 / =

1 8 12 - - 9 + 25 5 / * =