一年级上册数学课件 20以内数及其加减法（加法二） ▏沪教版 (共13张PPT) (1) 13页

请你算一算 11-1= 3+7= 10-3= 15-5= 2+8= 10-9= 12-2= 6+4= 10-5= 10 10 10 10 10 10 7 1 5 说说怎么算 8 + 6 = 9 + 3 = ① ② ① ② 12 8 + 2 = 10 10 + 4 = 14 14 9 + 1 = 10 10 + 2 = 12 退位减法 试一试： 14 – 5 = 仔细观察： 14 – 5 = ① 14 – 4 = 10 ② 10 – 1 = 9 ① 10 – 5 = 5 ② 5 + 4 = 9 9 1 2 3 0 19 18 5 6 8 4 10 11 12 9 14 15 16 13 17 7 20 14 – 5 = ① 14 – 4 = 10 ② 10 – 1 = 9 9 试一试： 想一想： 13 – 6 = 7 11 – 6 = 5 ① 13 – 3 = 10 ② 10 – 3 = 7 ① 11 – 1 = 10 ② 10 – 5 = 5 减数都是 6 ，为什么分拆得不一样呢？ 13 – 6 = 7 11 – 6 = 5 ① 13 – 3 = 10 ② 10 – 3 = 7 ① 11 – 1 = 10 ② 10 – 5 = 5 15 – 6 12 – 6 5 1 2 4 想一想： 用你喜欢的方法进行计算： 14 – 6 = 12 – 3 = ① ② ① ② 13 – 7 = 7 ① 13 – 5 = 9 ② 9 – 2 = 7 我来做小老师： × 13 – 7 = ① 13 – 3 = 10 ② 10 – 4 = 6 6 11 – 4 = 7 ① 10 – 4 = 6 ② 6 + 1 = 7 √ 我来做小老师： × 14 – 9 = ① 10 – 9 = 1 ② 4 + 1 = 5 3 14 – 9 = 3 ① 10 – 9 = 1 ② 4 - 1 = 3 我来做小老师： 看看你能得几颗 ★ ： 17 – 9 = 14 – 7 = ★ ★ ★ ★ ① ② ① ② ① ② ① ②