90 * 6 = 540;
900 * 6 = 5400;
9000 * 6 = 54000;
810 : 9 = 90;
8100 : 9 = 900;
81000 : 9 = 9000;
140 − 9 * 5 = 140 − 45 = 95;
150 − 7 * 8 = 150 − 56 = 94;
160 − 8 * 8 = 160 − 64 = 96;
88 : 22 * 10 = 4 * 10 = 40;
77 : 11 * 100 = 7 * 100 = 700;
96 : 32 * 1000 = 3 * 1000 = 3000.