Давай вычислим значения выражений, используя свойства умножения.
1) 12 \(\cdot\) 6 \(\cdot\) 4 \(\cdot\) 5 = 12 \(\cdot\) 4 \(\cdot\) 6 \(\cdot\) 5 = (12 \(\cdot\) 4) \(\cdot\) (6 \(\cdot\) 5) = 48 \(\cdot\) 30 = 1440
2) 16 \(\cdot\) 5 \(\cdot\) 9 \(\cdot\) 10 = 16 \(\cdot\) 9 \(\cdot\) 5 \(\cdot\) 10 = (16 \(\cdot\) 9) \(\cdot\) (5 \(\cdot\) 10) = 144 \(\cdot\) 50 = 7200
3) 6 \(\cdot\) 7 \(\cdot\) 5 \(\cdot\) 4 = 6 \(\cdot\) 7 \(\cdot\) 5 \(\cdot\) 4 = (6 \(\cdot\) 7) \(\cdot\) (5 \(\cdot\) 4) = 42 \(\cdot\) 20 = 840
4) 500 \(\cdot\) 2 \(\cdot\) 7 \(\cdot\) 3 = 500 \(\cdot\) 2 \(\cdot\) 7 \(\cdot\) 3 = (500 \(\cdot\) 2) \(\cdot\) (7 \(\cdot\) 3) = 1000 \(\cdot\) 21 = 21000
5) 49 \(\cdot\) 5 = (50 - 1) \(\cdot\) 5 = 50 \(\cdot\) 5 - 1 \(\cdot\) 5 = 250 - 5 = 245
6) 65 \(\cdot\) 8 = (60 + 5) \(\cdot\) 8 = 60 \(\cdot\) 8 + 5 \(\cdot\) 8 = 480 + 40 = 520
7) 6 \(\cdot\) 8 \(\cdot\) 5 \(\cdot\) 3 = 6 \(\cdot\) 3 \(\cdot\) 8 \(\cdot\) 5 = (6 \(\cdot\) 3) \(\cdot\) (8 \(\cdot\) 5) = 18 \(\cdot\) 40 = 720
Ответ: 1440; 7200; 840; 21000; 245; 520; 720
Отлично! Ты хорошо применяешь свойства умножения для упрощения вычислений. Так держать, и все примеры будут тебе по плечу!