X4. Calculează
121 + (2x 5 x 9) =
326 + (4 x 2 x 7) =
518 + (3 x 3 x 9) =
643 + (3 x 2 x 10) -
731 - (2 x 4 x 9) =
215 - (1 x 0 x 8) =
331 - (3 x 2 x 7)
147 - (6 x 1 x 6) =​