小学一年级奥数口算题：整十数加整十数的加法
(1)80 + 10 =
(2)30 + 20 =
(3)40 + 40 =
(4)50 + 30 =
(5)60 + 10 =
(6)80 + 10 =
(7)40 + 30 =
(8)20 + 60 =
(9)20 + 20 =
(10)40 + 40 =
(11)60 + 10 =
(12)20 + 10 =
(13)60 + 20 =
(14)30 + 40 =
(15)50 + 10 =