小升初面试数学速算游戏 24点相当好玩1Word文档格式.docx
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依据20+4=24,可得4×
4+4+4=24,
依据25-1=24,可得5×
5-5÷
5=24,
依据12+12=24,可得(6+6+(6+6=24,
练习题
1.在“24”点游戏中提出了下面几组牌,你能很快求出“24”吗?
(11,3,5,7(22,5,7,9
(31,3,9,10(410,4,10,4
(5K,Q,J,J(6Q,10,Q,1
(410×
10=100是4的25倍,100-4=96,正好是4的24倍,所以可以这样做(10×
10-4÷
(5K,Q,J,J即13,12,11,11,依据25-1=24可得13+12-11÷
11=24
(6Q,10,Q,1即12,10,12,1,依据12×
2=24可得12×
(12-10×
1=24
(1(5+7×
(3-1=24(25×
7-9-2=24
(3(1+10×
3-9=24(4(10×
(513+12-11÷
11=24(612×
2.在“24”点游戏中,抽出了下面两组牌,你能求出“24”吗?
(13,3,7,7(21,5,5,5
(1用常用的方法无论怎么求都不能得出“24”,是否就没有办法了呢?
当然不是,用乘法分配律的方法就可以求解
(3+3÷
7×
7
=3×
7+3÷
=24
(2用同样的方法求解
(5-1÷
5
=5×
5-1÷
(1(3+3÷
7=24
(2(5-1÷
5=24
熟练地掌握运算定律可以把题目化难为易,这里安排这两个题是为了开阔同学们的眼界,拓宽同学们的思路。
3.抽的四张牌恰好是“1~9”中从大到小连续排列的四张,这样的牌能算出“24”吗?
符合要求的组合有六组:
即9,8,7,6;
8,7,6,5;
6,5,4;
6,5,4,3;
5,4,3,2;
4,3,2,1不难发现它们均可求出24点。
(1依据4×
6=24得8÷
(9-7×
6=24
(2依据2×
12=24得(7+5×
(8-6=24
(3依据2×
12=24得(5+7×
(6-4=24
(4依据4×
6=24得2×
(3+4+5=24
(5依据4×
6=24得1×
2×
这个例子告诉我们不论从大到小,还是从小到大,连续取“1~9”中任意四个数均可凑成“24”。
巧算24点
“算24点”是一种数学游戏,正如象棋、围棋一样是一种人们喜闻乐见的娱乐活动。
它始于何年何月已无从考究,但它以自己独具的数学魅力和丰富的内涵正逐渐被越来越多的人们所接受。
这种游戏方式简单易学,能健脑益智,是一项极为有益的活动。
“算24点”的游戏内容如下:
一副牌中抽去大小王剩下52张,(如果初练也可只用1~10这40张牌任意抽取4张牌(称牌组,用加、减、乘、除(可加括号把牌面上的数算成24。
每张牌必须用一次且只能用一次,如抽出的牌是3、8、8、9,那么算式为(9—8×
8×
3或(9—8÷
3等。
“算24点”作为一种扑克牌智力游戏,还应注意计算中的技巧问题,不能瞎碰乱凑。
这里向大家介绍几种常用的、便于学习掌握的方法:
1.利用3×
8=24、4×
6=24求解。
把牌面上的四个数想办法凑成3和8、4和6,再相乘求解。
如3、3、6、10可组成(10—6÷
3=24等。
又如2、3、3、7可组成(7+3—2×
3=24等。
实践证明,这种方法是利用率最大、命中率最高的一种方法。
2.利用0、11的运算特性求解。
如3、4、4、8可组成3×
8+4—4=24等。
又如4、5、J、K可组成11×
(5—4+13=24等。
3.最为广泛的是以下七种解法(我们用a、b、c、d表示牌面上的四个数
①(a—b×
(c+d如(10—4×
(2+2=24等。
②(a+b÷
c×
d如(10+2÷
4=24等。
③(a-b÷
d如(3—2÷
12=24等。
④(a+b-c×
d如(9+5—2×
2=24等。
⑤a×
b+c—d如11×
3+l—10=24等。
⑥(a-b×
c+d如(4—l×
6+6=24等。
⑦(a×
b÷
(c+d如(6×
8÷
(1+1=24等。
需要说明的是:
一副牌(52张中,任意抽取4张可有1820种不同组合,其中有458个牌组算不出24点,如A、A、A、5。
“巧算24点”能极大限度地调动眼、脑、手、口、耳多种感官的协调活动,对于培养我们快捷的心算能力和反应能力很有帮助,还能帮助提高数学成绩。
你也来试试“巧算24点”吧,相信你会很快喜欢上它的!
例题参考:
1118(1+1+1*8=241126(1+1+2*6=24
1127(1+2*(1+7=241128(1*1+2*8=24
1129:
(1+2*(9-1=2411210:
(1+1*(2+10=24
1134:
(1+1*3*4=241135:
(1+3*(1+5=24
1136:
(1*1+3*6=241137:
(1*1+7*3=24
1138:
(1-1+3*8=241139:
(1+1*(3+9=24
11310:
(10-(1+1*3=241144:
(1+1+4*4=24
1145:
(1*1+5*4=241146:
(1-1+4*6=24
1147:
(7-1*1*4=241148:
(1+1*(4+8=24
1149:
(4-1*(9-1=2411410:
(1+1*10+4=24
1155:
5*5-1*1=241156:
(5-1*1*6=24
1157:
(1+1*(5+7=241158:
(5-(1+1*8=24
1166:
(1+1*(6+6=241168:
6*8/(1+1=24
1169:
(1+1*9+6=2411710:
(1+1*7+10=24
1188:
(1+1*8+8=241224:
(1+2*2*4=24
1225:
(1+5*(2+2=241226:
(1+2*(2+6=241227:
(7-1*(2+2=241228:
(2-1+2*8=241229:
(1+2+9*2=2412210:
(1+2*(10-2=241233:
(1+3*2*3=241234:
(1+2+3*4=241235:
(1+2*(3+5=241236:
(3-1+2*6=241237:
1+2+3*7=241238:
(2-1*3*8=241239:
3*9-(1+2=2412310:
(10-1*2*3=241244:
(1+2*(4+4=241245:
(5-1+2*4=241246:
(2-1*4*6=241247:
(1-2+7*4=241248:
(1-2+4*8=241249:
(9-(1+2*4=2412410:
1*2*10+4=241255:
1-2+5*5=241256:
(1-2+5*6=241257:
1*2*(5+7=241258:
(5-1*2*8=241259:
(1+2*5+9=2412510:
2*10-1+5=241266:
(1+2*6+6=241267:
(7-(1+2*6=241268:
(6-(1+2*8=241269:
1*2*9+6=2412610:
(1+2*10-6=241277:
(7*7-1/2=241278:
(1+7*2+8=241279:
2*9-1+7=2412710:
1*2*7+10=241288:
1*2*8+8=241289:
8*9/(1+2=2412810:
10+(8-1*2=241333:
(1+3*(3+3=241334:
(1*3+3*4=241335:
1*3*(3+5=241336:
(6-1+3*3=241337:
1*3+3*7=24
1338:
(1+8*3-3=241339:
(1+3*(9-3=2413310:
(1-3+10*3=241344:
(4-1+3*4=241345:
1+3+4*5=241346:
6/(1-3/4=241347:
4*7-(1+3=241348:
(1+3*4+8=241349:
(9-1*3*4=2413410:
(1+3*(10-4=241356:
(1+5*3+6=241357:
(3-1*(5+7=241358:
(1-3+5*8=241359:
1*3*5+9=2413510:
3*10-(1+5=241366:
(1-3+6*6=241367:
(7-1*3*6=241368:
(6-1*3*8=241369:
6+(3-1*9=2413610:
1*3*10-6=241377:
(7-1*(7-3=241378:
(7-(1+3*8=241379:
(1+7*9/3=2413710:
10+(3-1*7=241388:
(1+3*8-8=241389:
8*9/1*3=2413810:
(10-1/3*8=241399:
(9-1/3*9=2413910:
(1+10*3-9=24131010:
1+3+10+10=241444:
(1+4*4+4=241445:
1*4+4*5=241446:
(1+6*4-4=241447:
4*7-1*4=241448:
1*4*4+8=241449:
(1-4+9*4=2414410:
1*4*(10-4=241455:
4*5-(1-5=241456:
6/(5/4-1=241457:
1-5+4*7=241458:
(1+5*(8-4=241459:
9-(1-4*5=2414510:
(1-5*(4-10=241466:
(1+4*6-6=24
1467:
(1-4+7*6=241468:
(1-4+6*8=241469:
(9-(1+4*6=2414610:
(4-1*10-6=241477:
(1+7*(7-4=241478:
(7-1*4*8=241479:
(1-9*(4-7=241488:
(8-(1+4*8=241489:
8*9/(4-1=2414910:
1+4+9+10=24141010:
1*4+10+10=241555:
(5-1/5*5=241556:
(1+5*5-6=241559:
(1+5*(9-5=2415510:
(10-5*5-1=2415661*5*6-6=241567:
1-7+5*6=24
1568:
(1-5+8*6=24
1569:
(9-1*5*6=24
15610:
(1+5*(10-6=24
1578:
(1-5+7*8=24
1579:
(1-7*(5-9=24
15710:
5*7-(1+10=24
1588:
(8-1*5*8=24
1589:
(9-(1+5*8=24
15810:
1+5+8+10=24
1599:
1+5+9+9=24
15910:
1*5+9+10=24
151010:
(10+10-(1-5=24
1666:
(6-1*6-6=24
1668:
6/(1-6/8=241669:
(1-6+9*6=2416610:
1*6*(10-6=241679:
(1+7*(9-6=2416710:
1+6+7+10=241688:
(1-6+8*8=241689:
1+6+8+9=2416810:
1*6+8+10=241699:
1*6+9+9=2416910:
(9+10-(1-6=241779:
1+7+7+9=2417710:
(1+7*(10-7=241788:
1+7+8+8=241789:
1*7+8+9=2417810:
(8+10-(1-7=241799:
(9+9-(1-7=2417910:
(1-9*(7-10=241888:
1*8+8+8=241889:
(8+9-(1-8=2418810:
(1-8+10*8=242223:
(2+2*2*3=242224:
(2+2+2*4=24
2225:
(2*5+2*2=242227:
(2*7-2*2=242228:
(2+2*(8-2=242229:
(2+9*2+2=2422210:
2+2+2*10=242233:
(2+2*(3+3=242234:
(2+2+4*3=242235:
(2*5-2*3=242236:
(2/2+3*6=242237:
(2/2+7*3=242238:
(2-2+3*8=242239:
(2+2*(9-3=2422310:
(3+10*2-2=242244:
(2*4-2*4=242245:
2+2+4*5=242246:
(2-2+4*6=242247:
4*7-(2+2=242248:
(2+2*4+8=242249:
2+4+2*9=2422410:
(2+2*(10-4=242255:
5*5-2/2=242256:
(5-2/2*6=24
2257:
2*5+2*7=242258:
(5+8*2-2=242259:
(9-(2-5*2=2422510:
(2+5*2+10=242266:
(2+6/2*6=242267:
(2+7*2+6=242268:
(8-(2+2*6=242269:
(6/2+9*2=2422610:
2*10-(2-6=242277:
(7-(2-7*2=242278:
(7-(2+2*8=2422710:
(10/2+7*2=242288:
(2+2*8-8=242289:
2*9-(2-8=2422810:
2*8-2+10=2422910:
10-(2-9*2=24221010:
2+2+10+10=242333:
(2+3+3*3=242335:
(2+5*3+3=242336:
(3-(2-3*6=242337:
2*3*(7-3=242338:
(2*3-3*8=24
23310:
3*10-2*3=242344:
(2+3*4+4=242345:
(5-(2-3*4=242346:
(3-2*4*6=242347:
(2-3+7*4=242348:
(2-3+4*8=242349:
2/3*4*9=2423410:
3*10-(2+4=242355:
2-3+5*5=242356:
(2-3+5*6=242357:
3*7-(2-5=242358:
2*8+3+5=242359:
2*3*(9-5=2423510:
(2+10*(5-3=242366:
(2+3*6-6=242367:
6/2+3*7=242368:
(2+8*3-6=242369:
(9-(2+3*6=2423610:
2*3*(10-6=242377:
2*7+3+7=242378:
(2+7/3*8=24
23710:
2*10-3+7=242388:
(8-(2+3*8=242389:
(9-2*3*8=2423810:
2*3+8+10=242399:
2*3+9+9=2423910:
2+3+9+10=24231010:
10-(3-10*2=242444:
(4-(2-4*4=242445:
(2+5*4-4=242446:
(2*4-4*6=242447:
2*4*(7-4=242448:
(2+4*(8-4=242449:
(9-2*4-4=2424410:
4-(2-4*10=242455:
(5+5*2+4=242456:
(2+4*5-6=242457:
(5+7/2/4=242458:
(2-4+5*8=242459:
(2+4*(9-5=2424510:
2*5+4+10=242466:
(2-4+6*6=24
2468:
2/4*6*8=242469:
2*4*(9-6=2424610:
(2+4*(10-6=242477:
(7+7*2-4=242478:
(2*7-8*4=242479:
2*4+7+9=2424710:
10-(2-4*7=242488:
8-(2-4*8=242489:
(9-(2+4*8=2424810:
2+4+8+10=242499:
2+4+9+9=2424910:
2*9-4+10=24241010:
(4/10+2*10=242557:
2*7+5+5=242558:
(5/5+2*8=242559:
9-(2-5*5=2425510:
(5-2/10*5=242566:
6-(2-5*6=242567:
(2-5+7*6=242568:
(2-5+6*8=242569:
6/2*5+9=24
2577:
2*5+7+7=242578:
(2*5-7*8=242579:
5*7-(2+9=2425710:
2+5+7+10=242588:
5*8-2*8=242589:
2+5+8+9=2425810:
(10-(2+5*8=2425910:
2*10-5+9=24251010:
(2+10/5*10=242666:
2*6+6+6=242667:
(7-6/2*6=242668:
2*6*(8-6=242669:
(2+6*(9-6=2426610:
2+6+6+10=242678:
(2-6+7*8=242679:
2+6+7+9=2426710:
(2+6*(10-7=242688:
2+6+8+8=242689:
2/6*8*9=2426810:
2*6*(10-8=242699:
(6/9+2*9=24
26910:
(2-10*(6-9=24261010:
(10+10-(2-6=242778:
2+7+7+8=2427710:
(10/7+2*7=242788:
(2-7+8*8=242789:
(7+9*2-8=2427910:
(9+10-(2-7=24271010:
(2-10*(7-10=242888:
8/2*8-8=24
2889:
(2-8+9*8=2428810:
(8+10-(2-8=242899:
(9+9-(2-8=2428910:
(2-9+10*8=24281010:
8/2+10+10=24291010:
10/2+9+10=243333:
3*3*3-3=243334:
(3*3-3*4=243335:
3*3+3*5=243336:
(3+3*3+6=243337:
(3+3*(7-3=243338:
(3+3-3*8=243339:
(9-3/3*3=24
3344:
3*4+3*4=243345:
(3/3+5*4=243346:
(3-3+4*6=243347:
(7-3/3*4=243348:
(3+3*(8-4=243349:
3*4+3+9=243355:
5*5-3/3=243356:
(3+3*5-6=243357:
(3*5-7*3=243359:
(3+3*(9-5=2433510:
3*3+5+10=243366:
(6/3+6*3=243367:
3*7-(3-6=243368:
(3*3-6*8=243369:
3*3+6+9=2433610:
(3+3*(10-6=243377:
(3/7+3*7=243378:
3*3+7+8=243379:
(3-7*(3-9=243388:
8/(3-8/3=243389:
(9-(3+3*8=24
3399:
3+3+9+9=2433910:
3-9+3*10=243444:
(3+4*4-4=243445:
(5-(3-4*4=243446:
3*4*(6-4=243447:
(3-4+7*4=243448:
(3+4-4*8=243449:
4*9-3*4=2434410:
(10-3*4-4=243455:
3-4+5*5=243456:
(3-4+5*6=243457:
3*4+5+7=243458:
(3+5*4-8=243459:
(3*5-9*4=2434510:
3*4/5*10=243466:
3*4+6+6=243468:
3*4*(8-6=243469:
(3-6+9*4=2434610:
3*6-4+10=243477:
3-7+4*7=243478:
8-(3-7*4=24
3479:
3*4*(9-7=2434710:
3+4+7+10=243489:
3+4+8+9=2434810:
3*4*(10-8=243499:
(9+9/3*4=24341010:
3*10+4-10=243556:
(5+5*3-6=243557:
(5-3*(5+7=243558:
(3+5-5*8=243559:
(9-5/5*3=243566:
(3-5+6*6=243567:
(5+7/3/6=243568:
6*8/(5-3=243569:
(3+5*(9-6=2435610:
3+5+6+10=243578:
3*7-5+8=243579:
3+5+7+9=2435710:
(3+5*(10-7=243588:
3+5+8+8=243589:
3*9+5-8=243599:
9/3*5+9=2435910:
(3+9/5*10=24
351010:
(10-10/5*3=243666:
6-(3-6*6=243667:
6*7-3*6=243668:
(3+6-6*8=243669:
3+6+6+9=2436610:
(6-3*10-6=243677