6. Выполнить умножение: 91×17, 52×66, 33×41, 28×35.

91×17 = 91×(10+7) = 910+637 = 1547.

52×66 = 52×(60+6) = 3120+312 = 3432.

33×41 = 33×(40+1) = 1320+33 = 1353.

28×35 = 28×(30+5) = 840+140 = 980.