同时掷两颗骰子得到的点数共有36种情况,即 (1,1)(1,2)(1,3)(1,4)(1,5)(1,6), (2,1)(2,2)(2,3)(2,4)(2,5)(2,6), (3,1)(3,2)(3,3)(3,4)(3,5)(3,6), (4,1)(4,2)(4,3)(4,4)(4,5)(4,6), (5,1)(5,2)(5,3)(5,4)(5,5)(5,6), (6,1)(6,2)(6,3)(6,4)(6,5)(6,6), 而和为4的情况数有3种,即(1,3)(2,2)(3,1) 所以所求概率为
故答案为:
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