3 :8 = 3 :8
15 :4 = 15 :4
12.5 :40 = 125 :400 = 25 :80 = 5 :16
25 :60 = 5 :12
0.3 :1 / 2 = 0.3 :0.5 = 3 :5
24 :40 = 3 :8
0.2 :3 / 10 = 0.2 :0.3 = 2 :3
3.2 :4.8 = 32 :48 = 16 :24 = 8 :12 = 4 :6 = 2 :3
结论：
3 :8 和 24 :40 的比例相等,都等于 3 ：8
0.2 :3 / 10 和 3.2 :4.8 的比例相等,都等于 2 :3
3 :8 = 0.375
15 :4 = 3.75
12.5 :40 = 0.3125
25 :60 = 0.416.（ 6 循环）
0.3 :1 / 2 = 0.6
24 :40 = 0.375
0.2 :3 / 10 = 0.6.（ 6 循环）
3.2 :4.8 = 0.6.（ 6 循环）