【 练 习 题. 二 】 (破十法)
18 – 9 = 17 – 9 = 16 – 9 = 15 – 9 = 11 – 4=
14 – 9 = 13 – 9 = 12 – 9 = 11 – 9 = 12 – 3 =
17
– 8 = 13
– 8 =
15 – 7 =
11 – 7 =
12– 6 =
16 – 8 = 12 – 8 = 14 – 7 = 15 – 6 = – 6 = 15 – 8 = 11 – 8 = 13 – 7 = 14 – 6 = 14 – 5 = 14 – 8 = 16 – 7 = 12 – 7 = 13 – 6 = 13 – 5 = 11 – 3 = 11 – 2 = – 5 =
12 – 4=
13 – 4=
11 11
【 练 习 题. 三 】 (20以内退位减法)
破十法口诀:看大数,分出10;减小数,加剩数。
15 - 6 = 12 - 5 = 17 - 9 =
13 - 4 = 11
16 - 8 = 15
12 - 7 = 14
12 - 9 = 11
16 - 9 = 15
11 - 6 = 13
13 - 9 = 17 - 5 = 14 - 9 = 18 - 9 = 13 - 3 = - 8 = 13 - 4 = 14 - 8 = 14 - 7 = - 9 = - 7 = 12 - 4 = - 8 = - 5 = - 6=
【 练 习 题. 四 】 (凑十法)
1. 拆小数,凑大数
9 + 9 = 9 + 8 = 9 + 7 =
9 + 6 = 9 + 5 = 9 + 4 =
9 + 3 = 9 + 2 = 8 + 8 =
8 + 7 =
8 + 4 = 8 + 3 = 7 + 7 =
7 + 6 = 7 + 5 =
6 + 6 = 6 + 5 = 8 + 6 = 8 + 5 = 7 + 4 =
【 练 习 题. 五 】 (凑十法)
2. 拆大数,凑小数 9 + 9 = 8 + 9 = 7 + 9 =
6 + 9 = 5 + 9 = 4 + 9 =
3 + 9 = 2 + 9 = 8 + 8 =
7 + 8 = 6 + 8 = 5 + 8 =
4 + 8 = 3 + 8 = 7 + 7 =
6 + 7 = 5 + 7 = 4 + 7 = 6 + 6 = 5 + 6 =
【 练 习 题. 六 】 (凑十法)
5 + 6 =
6 + 6 =
6 + 8 =
7 + 7 =
7 + 4 = 6 + 5 = 5 + 7 = 7 + 6 = 5 + 9 = 9 + 7 = 6 + 9 = 7 + 5 = 5 + 8 = 8 + 5 = 9 + 5 =