第二单元2.4整理和复习（课件）人教版数学一年级下册

2.4整理和复习 人教版一年级下册 计算接力赛。 14－8＝ 13－6＝ 11－9＝ 17－8＝ 16－7＝ 15－6＝ 12－9＝ 11－5＝ 14－7＝ 11－3＝ 12－6＝ 13－8＝ 5 被减数 减数 差 … … … 情境引入 博学之，审问之，慎思之，明辨之，笃行之 天行健，君子以自强不息。地势坤，君子以厚德载物 打败小僵尸 13-8 14-7 16-7 11-9 11-4 14-6 12-6 12-9 13-7 15-8 12-7 15-6 16-8 18-9 11-6 12-3 18-9 16-5 11-9 13-6 返回 通关 博学之，审问之，慎思之，明辨之，笃行之 天行健，君子以自强不息。地势坤，君子以厚德载物 11 – 2 11 – 3 11 – 5 11 – 6 11 – 7 11 – 9 11 – 8 11 – 4 12 – 9 13 – 9 14 – 9 17 – 9 15 – 9 16 – 9 18 – 9 小组活动1 按一定的顺序摆出退位减法表。 活动要求： 1、小组合作先计算出所有的算式。 2、想一想排列的方法和顺序 ，再合作排列出退位减法表。 探索新知 博学之，审问之，慎思之，明辨之，笃行之 天行健，君子以自强不息。地势坤，君子以厚德载物 13 – 4 = 9 12 – 3= 9 11 – 2 = 9 11 – 3 = 8 12 – 4 = 8 12 – 5 = 7 12 – 9 = 3 12 – 6 =6 12 – 7 = 5 12 – 8 = 4 11 – 5 = 6 11 – 6 = 5 11 – 7 = 4 11 – 9 = 2 11 – 8 = 3 11 – 4 = 7 13 – 5 = 8 13 – 6 = 7 13 – 7 = 6 13 – 8 = 5 13 – 9 = 4 14 – 9 = 5 14 – 6 = 8 14 – 5 = 9 14 – 7 = 7 14 – 8= 6 17 – 9 = 8 15 – 7 = 8 15 – 9 = 6 15 – 8= 7 15 – 6 = 9 16 – 7 = 9 16 – 9 = 7 16 – 8= 8 17 – 8 =9 18 – 9 = 9 小组活动2 观察表格,发现规律。 活动要求： 先从不同方向观察减法表，再把你的发现和同组同学说一说。 博学之，审问之，慎思之，明辨之，笃行之 天行健，君子以自强不息。地势坤，君子以厚德载物 观察表格,发现规律 11 – 2 = 9 11 – 3 = 8 11 – 5 = 6 11 – 6 = 5 11 – 7 = 4 11 – 9 = 2 11 – 8 = 3 11 – 4 = 7 13 – 4 = 9 12 – 3= 9 12 – 4 = 8 12 – 5 = 7 12 – 9 = 3 12 – 6 =6 12 – 7 = 5 12 – 8 = 4 13 – 5 = 8 13 – 6 = 7 13 – 7 = 6 13 – 8 = 5 13 – 9 = 4 14 – 9 = 5 14 – 6 = 8 14 – 5 = 9 14 – 7 = 7 14 – 8= 6 17 – 9 = 8 15 – 7 = 8 15 – 9 = 6 15 – 8= 7 15 – 6 = 9 16 – 7 = 9 16 – 9 = 7 16 – 8= 8 17 – 8 =9 18 – 9 = 9 -1 -1 -1 -1 -1 -1 -1 +1 +1 +1 +1 +1 +1 +1 11 11 11 11 11 11 11 11 横着看 被减数不变， 减数连续减1， 差连续加1。 博学之，审问之，慎思之，明辨之，笃行之 天行健，君子以自强不息。地势坤，君子以厚德载物 观察表格,发现规律 11 – 2 = 9 11 – 3 = 8 11 – 5 = 6 11 – 6 = 5 11 – 7 = 4 11 – 9 = 2 11 – 8 = 3 11 – 4 = 7 12 – 3= 9 12 – 4 = 8 12 – 5 = 7 12 – 9 = 3 12 – 6 =6 12 – 7 = 5 12 – 8 = 4 13 – 4 = 9 13 – 5 = 8 13 – 6 = 7 13 – 7 = 6 13 – 8 = 5 13 – 9 = 4 14 – 9 = 5 14 – 6 = 8 14 – 5 = 9 14 – 7 = 7 14 – 8= 6 17 – 9 = 8