Завдання:
Виконай множення зручним способом:
1) –0,2 ⋅ 31 ⋅ (–5);
2) –2 ⋅ (–0,5) ⋅ 117;
3) 0,25 ⋅ (–19) ⋅ (–40);
4) –0,125 ⋅ (–7,2) ⋅ (–80);
5) –20 ⋅ (–17,2) ⋅ (–5);
6) –500 ⋅ 12 ⋅ 0,03 ⋅ (–2).
Розв'язок:
1) -0,2 ⋅ 31 ⋅ (-5) = (-0,2 ⋅ (-5)) ⋅ 31 = 1 ⋅ 31 = 31
2) -2 ⋅ (-0,5) ⋅ 117 = (-2 ⋅ (-0,5)) ⋅ 117 = 1 ⋅ 117 = 117
3) 0,25 ⋅ (-19) ⋅ (-40) = (0,25 ⋅ (-40)) ⋅ (-19) = -10 ⋅ (-19) = 190
4) -0,125 ⋅ (-17,2) ⋅ (-80) = (-0,125 ⋅ (-80)) ⋅ (-7,2) = 10 ⋅ (-7,2) = -72
5) -20 ⋅ (-17,2) ⋅ (-5) = (-20 ⋅ (-5)) ⋅ (-17,2) = 100 ⋅ (-17,2) = -1720
6) -500 ⋅ 12 ⋅ 0,03 ⋅ (-2) = (-500 ⋅ (-2)) ⋅ (12 ⋅ 0,03) = -1000 ⋅ (-0,36) = 360