不挂科搜题免费

问题:

凑十法练习题。(1) 7 + 8 = ?(2) 6 + 9 = ?(3) 4 + 7 = ?(4)

答案:

(1) 7 + 8 = 7 + 3 + 5 = 10 + 5 = 15。(2) 6 + 9 = 6 + 4 + 5 = 10 + 5 = 15。(3) 4 + 7 = 4 + 6 + 1 = 10 + 1 = 11。(4) 3 + 8 = 3 + 7 + 1 = 10 + 1 = 11。(5) 5 + 6 = 5 + 5 + 1 = 10 + 1 = 11。