18 : 2 * 10;
14 : 7 * 8;
18 : 9 * 7;
12 : 6 * 8;
10 : 5 * 6;
8 : 2 * 10;
1 * 5;
1 * 87.
18 : 2 * 10 = 9 * 10;
14 : 7 * 8 = 2 * 8 = 16;
18 : 9 * 7 = 2 * 7 = 14;
12 : 6 * 8 = 2 * 8 = 16;
10 : 5 * 6 = 2 * 6 = 12;
8 : 2 * 10 = 4 * 10 = 40;
1 * 5 = 5;
1 * 87 = 87.