2, 4, 5, 6, 8, 10, 12
0, 1, 2, 3, 4, 5, 6, 7, 8, 9
-10, -12, -15, 0, 1, 2, 3, 4
5
1, 2, 3, 4, 5, 6, 7, 8, 9
2/3, 25/2, 0.1, 2.5, 1, 5, -5
10, 20, 30, 40, 50
1, 2, 3, 4, 5, 6, 7, 8, 9... +∞
276/34
-∞...... +∞
-3, -2, -1. 0. 1. 2, 3... +∞
1,2,3,4,5,.....+∞
0,1,2,3,4,5,6,7,8,9
4/2, 3/4. 12/9
1/5
