不进位加法和不退位减法
第2课时
15 + 2 = 14 + 1 = 20– 10 =
16 - 3 = 18 – 3 = 13 + 4 =
19– 4 = 13 + 4 = 16 – 5 =
12 + 5 = 17 – 7 = 16 + 0 =