1+2=3, 3+1=4; 3+4=7, 7+3=10;7+10=17,17+7=24; 17+24=41, 41+17=58;41+58=99, 99+41=140; 99+140=239, 239+99=338;239+338=577, 577+239=816; 577+816=1393, 1393+577=1970;1393+1970=3363, 3363+1393=4756。第 10个数是3363/4756
2785/3940
3363/4756