Вправи: 1178

1178. Обчисліть зручним способом:

1) –5 • 17 • (–20) = –5 • (–20) • 17 = 100 • 17 = 1700;

2) 12 • (–25) • 4 = 12 • (–100) = –1200;

3) –4 • (–2,5) • (–7) = 10 • (–7) = –70;

4) –0,5 • (–15) • 20 = –0,5 • 20 • (–15) = –10 • (–15) = 150;

5) 2,59 • 250 • (–4) = 2,59 • (–1000) = –2590;

6) –125 • 1,5 • (–8) • 6 = –125 • (–8) • 1,5 • 6 = 1000 • 9 = 9000;

7) –8 • (–2,5) • (–1,25) • (–4) = –8 • (–1,25) • (–2,5) • (–4) = 10 • 10 = 100;

8) –4 • (–0,2) • 9 • (–5) • (–25) = –4 • (–25) • (–0,2) • (–5) • 9 = 100 • 1 • 9 = 900.