用1-10这10个数可以组成多少组由不同4个数字组成的组数?答:2345,2346,2347,2348,2349 2356,2357,2358,2359 2367,2368,2369 2378,2379 2389 2456,2457,2458,2459 2467,2468,2469 2478,2479 2489 2567,2568,2569 2578,2579 2589 2678,2679 2689 2789...35组 3456,3457,3458,3459 3467,3468,3469 3478,3479 3489 3567,3568,3569 3578,3579 3589 3678,3679...