1) 572 • 10 = 5720;
2) 100 • 7982 = 798 200;
3) 52 • 1000 = 52 000;
4) 8 • 7 • 5 = (8 • 5) • 7 = 40 • 7 = 280;
5) 7 • 20 • 5 = 7 • (20 • 5) =7 • 100 = 700;
6) 4 • 8 • 25 = (4 • 25) • 8 = 8 • 100 = 800;
7) 43 • 10 • 2 = (43 • 2) • 10 = 86 • 10 = 860;
8) 5 • 9 • 2 • 7 = (9 • 7) • (5 • 2) = 63 • 10 = 630;
9) 10 • 2 • 7 • 50 = (7 • 10) • (2 • 50) = 70 • 100 = 7000.