№ 3. Вычислите, выбирая удобный способ: a) 25. 289. 4; 6) 8.971. 125; в) 50. 93. 20; г) 400.34.500.

a) 25 ⋅ 289 ⋅ 4 = (25 ⋅ 4) ⋅ 289 = 100 ⋅ 289 = 28900

б) 8 ⋅ 971 ⋅ 125 = (8 ⋅ 125) ⋅ 971 = 1000 ⋅ 971 = 971000

в) 50 ⋅ 93 ⋅ 20 = (50 ⋅ 20) ⋅ 93 = 1000 ⋅ 93 = 93000

г) 400 ⋅ 34 ⋅ 500 = (400 ⋅ 500) ⋅ 34 = 200000 ⋅ 34 = 6800000

Ответ: a) 28900; б) 971000; в) 93000; г) 6800000