1、小学一年级数学上册-凑十法-破十法-借十法-练习习题 小学一年级上册数学试题加法 与 减法进位加法(凑十法口诀:看大数,分小数,凑成十,算得数。)退位减法(破十法口诀:看大数,分出10,减小数,加剩数。)借十法(十几减9,几加1;几减8,几加2;十几减7,几加3;十几减6,几加4;十几减5,几加5;十几减4,几加6;十几减3,几加7;十几减2,几加8;十几减1,几加9.)一、“凑十法:1.“凑十法是20以内进位加法的根本思路。运用“凑十法能够将20以内的进位加法转化为学生所熟悉的10加几的题目,从而化难为简。那么“凑十法在具体计算中是如何“凑十的呢,我们看以下例题:在计算9+4时,先把4分成1
2、和3,然后9和1凑成10,10再加上3等于13;这就是“凑十法。2.“凑十歌:1凑9 2凑8 3凑7来4凑6 5、5相凑正满10 做减做加想到它,又对又快真方便!3.“凑十法具有很强的规律性,不仅可以在解决20以内进位加法的计算中用到,在不进位加法中也可以用到。以下边例子说明:如在计算14+5时,先把14分成10和4,然后4和5先加等于9,然后再和前边的10相加等于19; “借十法(破十法):1.“借十法是用在20以内退位减法中的计算方法。运用“借十法可将20以内的退位减法转化为学生所熟悉的10减几的题目,从而化难为简。那么“借十法在具体计算中是如何“凑十的呢,我们看以下例题:在计算13减4时
3、,先考虑个位3减4,不够减,于是从十位借10来减,10减4得6,再用6与个位数3相加等于9;这就是“借十法。2.“借十法口诀:借十法,很简单;十几减9,几加1;十几减8,几加2;十几减7,几加3;十几减6,几加4;十几减5,几加5;十几减4,几加6;十几减3,几加7;十几减2,几加8;十几减1,几加9. 3.根据口诀与例题掌握“借十法。 凑 十 歌 一九一九好朋友, 二八二八手拉手, 三七三七真亲密, 四六四六一起走。五五凑成一双手。一加九,十只小蝌蚪, 二加八,十只花老鸭, 三加七,十只老母鸡, 四加六,十只金丝猴, 五加五,十只大老虎。 看到9想到1, 看到8想到2, 看到7想到3, 看到
4、6想到4。看到大数加小数,。一五6,二四6,三三6,四二6,五一6;6的组成没遗漏。一六7,二五7,三四7,四三7,五二7,六一7;7的组成记仔细。一七8,二六8,三五8,四四8,五三8,六二8,七一8;8的组成记全它。一八9,二七9,三六9,四五9,五四9,六三9,七二9,八一9; 9的组成全都有。 一九10,二八10,三七10,四六10,五五10,六四10,七三10,八二10,九一10;10的组成共九句。【 练 习 题. 一 】 (凑 十 法)9 + 6 = 9 + 5 = 9 + 4 = 9 + 3 = 9 + 2 = 9 + 7 =9 + 8 = 9 + 9 = 8 + 8 =8 +
5、7 = 8 + 9 = 8 + 6 =8 + 5 = 8 + 4 = 8 + 3 =7 + 9 = 7 + 8 = 7 + 7 =7 + 6 = 7 + 4 = 7 + 5 =6 + 9 = 6 + 8 = 6 + 7 =6 + 6 = 6 + 5 = 5 + 9 = 5 + 8 = 5 + 7 = 5 + 6 =4 + 9 = 4 + 8 = 4 + 7 =3 + 9 = 3 + 8 = 2 + 9 =【 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 = 16
6、 8 = 15 8 = 14 8 = 11 3 =13 8 = 12 8 = 11 8 = 16 7 = 11 2 =15 7 = 14 7 = 13 7 = 12 7 = 11 5 = 11 7 = 15 6 = 14 6 = 13 6 = 12 4= 12 6 = 11 6 = 14 5 = 13 5 = 13 4= 【 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 5 = 14 7 = 16 8 = 15 9 = 18 9 = 12 7 = 14 9 = 13 7 = 12 9 = 1
7、1 3 = 12 4 =16 9 = 15 8 = 13 8 =11 6 = 13 4 = 14 5 =13 9 = 17 8 = 14 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 + 6 = 8 + 5 =8 + 4 = 8 + 3 = 7 + 7 =7 + 6 = 7 + 5 = 7 + 4 =6 + 6 = 6 + 5 = 【 练 习 题. 五 】 (凑十法)2. 拆大数,凑小数9 + 9 = 8 + 9 = 7 +
8、 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)9 + 5 =9 + 7 =7 + 4 =8 + 5 =5 + 9 =7 + 7 =5 + 8 =7 + 6 =6 + 8 =7 + 5 =5 + 7 =6 + 6 =6 + 9 =6 + 5 =5 + 6 =9 + 5 =9 + 7 =7 + 4 =8 + 5 =5 + 9 =7 + 7 =
9、5 + 8 =7 + 6 =6 + 8 =7 + 5 =5 + 7 =6 + 6 =6 + 9 =6 + 5 =5 + 6 =【 练 习 题. 七 】 (凑十法)8 + 6 =9 + 5 =5 + 7 =7 + 6 =8 + 7 =5 + 9 =6 + 7 =5 + 7 =5 + 6 =7 + 8 =4 + 7 =5 + 6 =8 + 6 =9 + 5 =5 + 7 =7 + 6 =8 + 7 =5 + 9 =6 + 7 =5 + 7 =5 + 6 =7 + 8 =4 + 7 =5 + 6 =7 + 9 =9 + 5 =9 + 4 =9 + 4 =【 练 习 题. 八 】 (凑十法)15 -
10、6 = 14 - 5 = 13 - 4 =12 - 3 = 11 - 2 = 16 - 7 =17 - 8 = 18 - 9 = 16 - 8 =15 - 7 = 17 - 9 = 14 - 6 =13 - 5 = 12 - 4 = 11 - 3 =16 - 9 = 15 - 8 = 14 - 7 =13 - 6 = 11 - 4 = 12 - 5 =15 - 9 = 14 - 8 = 13 - 7 =12 - 6 = 11 - 5 = 14 - 9 = 13 - 8 = 12 - 7 = 11 - 6 =13 - 9 = 12 - 8 = 11 - 7 =12 - 9 = 11 - 8 =
11、11 - 9 =【 练 习 题. 九 】 (凑十法)1. 拆小数,凑大数,凑成10,再相加 。9 + 8 = 9 + 7 = 9 + 6 =9 + 5 = 9 + 4 = 9 + 3 =9 + 2 = 8 + 7 = 8 + 6 =8 + 5 = 8 + 4 = 8 + 3 =7 + 6 = 7 + 5 = 7 + 4 =6 + 5 = 【 练 习 题. 十 】 (凑十法)2. 拆大数,凑小数,凑成10,再相加 。8 + 9 = 7 + 9 = 6 + 9 =5 + 9 = 4 + 9 = 3 + 9 =2 + 9 = 7 + 8 = 6 + 8 =5 + 8 = 4 + 8 = 3 + 8
12、=6 + 7 = 5 + 7 = 4 + 7 =5 + 6 = 3.9 + 9 = 8 + 8 = 7 + 7 = 6 + 6 = 【 练 习 题. 十一 】 (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 + 6 = 8 + 5 =8 + 4 = 8 + 3 = 7 + 7 =7 + 6 = 7 + 5 = 7 + 4 =6 + 6 = 6 + 5 = 【 练 习 题. 十二 】 (凑十法)2. 拆大数,凑小数9 + 9 = 8 + 9 = 7 + 9
13、=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. 十三 】 (凑十法)一、用凑十法做一做。9 + 6 = 9 + 5 = 9 + 4 = 9 + 3 = 9 + 2 = 9 + 7 = 9 + 8 = 9 + 9 =8 + 8 = 8 + 7 = 8 + 9 = 8 + 6 =8 + 5 = 8 + 4 = 8 + 3 = 7 + 9 =7 + 8 = 7 + 7 = 7 + 6 = 7 + 4 =7 + 5 = 6 + 9 = 6 + 8 = 6 + 7 =6 + 6 = 6 + 5 = 5 + 9 = 5 + 8 = 5 + 7 = 5 + 6 = 4 + 9 = 4 + 8 =4 + 7 = 3 + 9 = 3 + 8 = 2 + 9 =【 练 习 题. 十四 】 (20以内退位减)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 5 = 14 7 = 16 8 = 15 9 = 18 9 = 12 7 = 14 9 = 13