4.2不进位加法和不退位减法（第三课时）课件-2025-2026学年西南大学版一年级数学上册

不进位加法和不退位减法（第三课时） 1 13+2=15 3+2=5 13+2=15 15-2=13 5-2=3 15-2=13 5 11+6=17(只) 1 6 1 +6=7 ？只 10+7=17 5 17只 ？只 17-6=11(只) 5 17只 ？只 17-11=6(只) 想：11+6=17 算：17-11=6 11+6=17(只) 17-6=11(只) 17-11=6(只) 17只 17只 ？只 ？只 ？只 5 11 + 6 = 17 (只) 17 17 6 6 11 11 - - = = (只) (只) 练习 1.看图列式。 + = - = - = + = （个） （个） （个） （个） 6 12 18 18 12 6 18 6 12 12 6 18 车上原有18人 车上原有18人 现在车上有多少人？ 18-4=14（人） 车上原有18人 车上原有18人 18-4=14（人） 车上原有18人 现在车上有多少人？ 6 车上原有18人 现在车上有多少人？ 学习要求： 1.请结合图片内容列出算式，并说说为什么这样列式。 2.说一说你是怎么计算的。 车上原有18人 18+1-4 +1 - 4 18 14 =15（人） 19 =15（人） 6 现在车上有多少人？ 只有加减法时，从左到右依次计算。 课堂活动 1.看图说算式。 树上有14只小鸟。 飞走了2只。 又飞来了3只。 树上现在有多少只小鸟？ 14 -2 +3 12 =15（只） 课堂活动 2.看算式卡片，讲数学故事。 16-4-2 有16块饼干，爸爸吃了4块，我吃了2块，还剩多少块呢？ 我有16元，买面包用去了4元，买矿泉水用去了2元，还剩多少元？ …… 只有加减法时，从左到右依次计算。 谢谢观看 Thank you 2 com.apple.VoiceMemos (iPhone (4) (null)) 3 com.apple.VoiceMemos (iPhone (4) (null)) 4 com.apple.VoiceMemos (iPhone (4) (null)) 5 com.apple.VoiceMemos (iPhone (4) (null)) 1 com.apple.VoiceMemos (iPhone (4) (null)) 6 com.apple.VoiceMemos (iPhone (4) (null)) 8 com.apple.VoiceMemos (iPhone (4) (null)) 7 com.apple.VoiceMemos (iPhone (4) (null)) 11 com.apple.VoiceMemos (iPhone (4) (null)) 12 com.apple.VoiceMemos (iPhone (4) (null)) 15 com.apple.VoiceMemos (iPhone (4) (null)) 13 com.apple.VoiceMemos (iPhone (4) (null)) 14 com.apple.VoiceMemos (iPhone (4) (null)) 16 com.apple.VoiceMemos (iPhone (4) (null)) 17 com.apple.VoiceMemos (iPhone (4) (null)) 18 com.apple.VoiceMemos (iPhone (4) (null)) 19 com.apple.VoiceMemos (iPhone (4) (null)) 22 com.apple.VoiceMemos (iPhone (4) (null)) 23 com.apple.VoiceMemos (iPhone (4) (null)) 24 com.apple.VoiceMemos (iPhone (4) (null)) 25 com.apple.VoiceMemos (iPhone (4) (null)) 26 com.apple.VoiceMemos (iPhone (4) (null)) 20 com.apple.VoiceMemos (iPhone (4) (null)) 21 com.apple.VoiceMemos (iPhone (4) (null)) 27 com.apple.VoiceMemos (iPhone (4) (null)) 28 com.apple.VoiceMemos (iPhone (4) (null)) 29 com.apple.VoiceMemos (iPhone (4) (null)) 30 com.apple.VoiceMemos (iPhone (4) (null)) 33 com.apple.VoiceMemos (iPhone (4) (null)) 31 com.apple.VoiceMemos (iPhone (4) (null)) 32 com.apple.VoiceMemos (iPhone (4) (null)) 37 com.apple.VoiceMemos (iPhone (4) (null)) 35 com.apple.VoiceMemos (iPhone (4) (null)) 36 com.apple.VoiceMemos (iPhone (4) (null)) $