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2025年小升初數(shù)學(xué)入學(xué)考試模擬題(能力提升型)-數(shù)論與組合問(wèn)題訓(xùn)練考試時(shí)間:______分鐘總分:______分姓名:______一、選擇題(本大題共10小題,每小題3分,共30分。下列每小題給出的四個(gè)選項(xiàng)中,只有一項(xiàng)是符合題目要求的。)1.小明有5顆紅珠子和3顆藍(lán)珠子,他要把這些珠子排成一排,要求相鄰的珠子顏色不同,那么他有多少種不同的排列方式呢?讓我們一起來(lái)思考吧!如果紅珠子和藍(lán)珠子數(shù)量一樣多,比如都是4顆,那么排列方式就有4×3=12種,對(duì)不對(duì)?但是這里紅珠子比藍(lán)珠子多一顆,所以排列方式會(huì)稍微復(fù)雜一些。我們可以先排紅珠子,再排藍(lán)珠子,也可以先排藍(lán)珠子,再排紅珠子。但是要注意,如果第一顆珠子是紅色,那么后面就只能排藍(lán)色,如果第一顆珠子是藍(lán)色,那么后面就只能排紅色。所以,我們可以先排第一顆珠子,有2種選擇,然后排剩下的珠子,有4×3=12種排列方式。所以,總共有2×12=24種不同的排列方式。2.一個(gè)班級(jí)有30名學(xué)生,其中男生比女生多8人,那么男生和女生各有多少人呢?這道題其實(shí)很簡(jiǎn)單,我們可以用方程來(lái)解。設(shè)女生人數(shù)為x,那么男生人數(shù)就是x+8。因?yàn)槟猩团悠饋?lái)一共是30人,所以我們可以列出方程:x+(x+8)=30。解這個(gè)方程,我們得到x=11,所以女生有11人,男生有19人。3.有一個(gè)三位數(shù),它的個(gè)位數(shù)字比十位數(shù)字大2,比百位數(shù)字小4,這個(gè)三位數(shù)是多少呢?我們可以先設(shè)個(gè)位數(shù)字為x,那么十位數(shù)字就是x-2,百位數(shù)字就是x+4。因?yàn)檫@是一個(gè)三位數(shù),所以百位數(shù)字不能為0,所以x+4必須大于0。又因?yàn)閭€(gè)位數(shù)字最大是9,所以x必須小于等于9。我們可以列出方程:x+(x-2)+(x+4)=100。解這個(gè)方程,我們得到x=7,所以這個(gè)三位數(shù)是765。4.有10個(gè)小朋友,他們要平均分成5組,每組2人,那么有多少種不同的分法呢?這道題其實(shí)和排列組合有關(guān),我們可以用組合數(shù)來(lái)解。因?yàn)槲覀円獜?0個(gè)小朋友中選出2人作為第一組,有10×9/2=45種選法。選出第一組后,還剩下8個(gè)小朋友,選出2人作為第二組,有8×7/2=28種選法。以此類推,直到選出第五組。但是,因?yàn)榻M的順序不影響結(jié)果,所以我們需要除以5組的排列數(shù),即5×4×3×2×1=120。所以,總共有45×28×21×15×10/120=252種不同的分法。5.有一個(gè)自然數(shù),它除以3余1,除以5余2,除以7余3,那么這個(gè)自然數(shù)最小是多少呢?這道題其實(shí)和同余方程有關(guān),我們可以用逐步增加的方法來(lái)解。首先,找到一個(gè)滿足除以3余1的自然數(shù),比如1,然后逐漸增加3,得到1,4,7,10,13,16,19,22,25,28,31,34,37,40,43,46,49,52,55,58,61,64,67,70,73,76,79,82,85,88,91,94,97,100,103,106,109,112,115,118,121,124,127,130,133,136,139,142,145,148,151,154,157,160,163,166,169,172,175,178,181,184,187,190,193,196,199,202,205,208,211,214,217,220,223,226,229,232,235,238,241,244,247,250,253,256,259,262,265,268,271,274,277,280,283,286,289,292,295,298,301,304,307,310,313,316,319,322,325,328,331,334,337,340,343,346,349,352,355,358,361,364,367,370,373,376,379,382,385,388,391,394,397,400,403,406,409,412,415,418,421,424,427,430,433,436,439,442,445,448,451,454,457,460,463,466,469,472,475,478,481,484,487,490,493,496,499,502,505,508,511,514,517,520,523,526,529,532,535,538,541,544,547,550,553,556,559,562,565,568,571,574,577,580,583,586,589,592,595,598,601,604,607,610,613,616,619,622,625,628,631,634,637,640,643,646,649,652,655,658,661,664,667,670,673,676,679,682,685,688,691,694,697,700,703,706,709,712,715,718,721,724,727,730,733,736,739,742,745,748,751,754,757,760,763,766,769,772,775,778,781,784,787,790,793,796,799,802,805,808,811,814,817,820,823,826,829,832,835,838,841,844,847,850,853,856,859,862,865,868,871,874,877,880,883,886,889,892,895,898,901,904,907,910,913,916,919,922,925,928,931,934,937,940,943,946,949,952,955,958,961,964,967,970,973,976,979,982,985,988,991,994,997,1000。但是,這個(gè)數(shù)太大了,我們需要找到一個(gè)更小的數(shù)。我們可以嘗試從200開始,逐漸增加,直到找到一個(gè)滿足所有條件的最小自然數(shù)。經(jīng)過(guò)嘗試,我們發(fā)現(xiàn)這個(gè)自然數(shù)是58。所以,這個(gè)自然數(shù)最小是58。6.有一個(gè)兩位數(shù),它的十位數(shù)字比個(gè)位數(shù)字大3,這個(gè)兩位數(shù)是兩個(gè)質(zhì)數(shù)之和,那么這個(gè)兩位數(shù)是多少呢?我們可以先設(shè)個(gè)位數(shù)字為x,那么十位數(shù)字就是x+3。因?yàn)檫@是一個(gè)兩位數(shù),所以十位數(shù)字不能為0,所以x+3必須大于0。又因?yàn)閭€(gè)位數(shù)字最大是9,所以x必須小于等于9。我們可以列出所有可能的兩位數(shù),然后判斷它們是否是兩個(gè)質(zhì)數(shù)之和。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)兩位數(shù)是37。因?yàn)?和7都是質(zhì)數(shù),且3+7=10,而10減去3就是7,所以37是兩個(gè)質(zhì)數(shù)之和。7.有一個(gè)自然數(shù),它除以4余1,除以5余2,除以6余3,那么這個(gè)自然數(shù)最小是多少呢?這道題其實(shí)和同余方程有關(guān),我們可以用逐步增加的方法來(lái)解。首先,找到一個(gè)滿足除以4余1的自然數(shù),比如1,然后逐漸增加4,得到1,5,9,13,17,21,25,29,33,37,41,45,49,53,57,61,65,69,73,77,81,85,89,93,97,101,105,109,113,117,121,125,129,133,137,141,145,149,153,157,161,165,169,173,177,181,185,189,193,197,201,205,209,213,217,221,225,229,233,237,241,245,249,253,257,261,265,269,273,277,281,285,289,293,297,301,305,309,313,317,321,325,329,333,337,341,345,349,353,357,361,365,369,373,377,381,385,389,393,397,401,405,409,413,417,421,425,429,433,437,441,445,449,453,457,461,465,469,473,477,481,485,489,493,497,501,505,509,513,517,521,525,529,533,537,541,545,549,553,557,561,565,569,573,577,581,585,589,593,597,601,605,609,613,617,621,625,629,633,637,641,645,649,653,657,661,665,669,673,677,681,685,689,693,697,701,705,709,713,717,721,725,729,733,737,741,745,749,753,757,761,765,769,773,777,781,785,789,793,797,801,805,809,813,817,821,825,829,833,837,841,845,849,853,857,861,865,869,873,877,881,885,889,893,897,901,905,909,913,917,921,925,929,933,937,941,945,949,953,957,961,965,969,973,977,981,985,989,993,997,1001。但是,這個(gè)數(shù)太大了,我們需要找到一個(gè)更小的數(shù)。我們可以嘗試從200開始,逐漸增加,直到找到一個(gè)滿足所有條件的最小自然數(shù)。經(jīng)過(guò)嘗試,我們發(fā)現(xiàn)這個(gè)自然數(shù)是59。所以,這個(gè)自然數(shù)最小是59。8.有一個(gè)三位數(shù),它的百位數(shù)字比十位數(shù)字大2,比個(gè)位數(shù)字大4,這個(gè)三位數(shù)是三個(gè)連續(xù)質(zhì)數(shù)之和,那么這個(gè)三位數(shù)是多少呢?我們可以先設(shè)個(gè)位數(shù)字為x,那么十位數(shù)字就是x+2,百位數(shù)字就是x+4。因?yàn)檫@是一個(gè)三位數(shù),所以百位數(shù)字不能為0,所以x+4必須大于0。又因?yàn)閭€(gè)位數(shù)字最大是9,所以x必須小于等于9。我們可以列出所有可能的兩位數(shù),然后判斷它們是否是三個(gè)連續(xù)質(zhì)數(shù)之和。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)三位數(shù)是238。因?yàn)?,3,5都是質(zhì)數(shù),且2+3+5=10,而10減去2就是8,所以238是三個(gè)連續(xù)質(zhì)數(shù)之和。9.有一個(gè)自然數(shù),它除以3余1,除以5余2,除以7余3,那么這個(gè)自然數(shù)最小是多少呢?這道題其實(shí)和同余方程有關(guān),我們可以用逐步增加的方法來(lái)解。首先,找到一個(gè)滿足除以3余1的自然數(shù),比如1,然后逐漸增加3,得到1,4,7,10,13,16,19,22,25,28,31,34,37,40,43,46,49,52,55,58,61,64,67,70,73,76,79,82,85,88,91,94,97,100,103,106,109,112,115,118,121,124,127,130,133,136,139,142,145,148,151,154,157,160,163,166,169,172,175,178,181,184,187,190,193,196,199,202,205,208,211,214,217,220,223,226,229,232,235,238,241,244,247,250,253,256,259,262,265,268,271,274,277,280,283,286,289,292,295,298,301,304,307,310,313,316,319,322,325,328,331,334,337,340,343,346,349,352,355,358,361,364,367,370,373,376,379,382,385,388,391,394,397,400,403,406,409,412,415,418,421,424,427,430,433,436,439,442,445,448,451,454,457,460,463,466,469,472,475,478,481,484,487,490,493,496,499,502,505,508,511,514,517,520,523,526,529,532,535,538,541,544,547,550,553,556,559,562,565,568,571,574,577,580,583,586,589,592,595,598,601,604,607,610,613,616,619,622,625,628,631,634,637,640,643,646,649,652,655,658,661,664,667,670,673,676,679,682,685,688,691,694,697,700,703,706,709,712,715,718,721,724,727,730,733,736,739,742,745,748,751,754,757,760,763,766,769,772,775,778,781,784,787,790,793,796,799,802,805,808,811,814,817,820,823,826,829,832,835,838,841,844,847,850,853,856,859,862,865,868,871,874,877,880,883,886,889,892,895,898,901,904,907,910,913,916,919,922,925,928,931,934,937,940,943,946,949,952,955,958,961,964,967,970,973,976,979,982,985,988,991,994,997,1000。但是,這個(gè)數(shù)太大了,我們需要找到一個(gè)更小的數(shù)。我們可以嘗試從200開始,逐漸增加,直到找到一個(gè)滿足所有條件的最小自然數(shù)。經(jīng)過(guò)嘗試,我們發(fā)現(xiàn)這個(gè)自然數(shù)是59。所以,這個(gè)自然數(shù)最小是59。10.有一個(gè)兩位數(shù),它是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是2,那么這個(gè)兩位數(shù)是多少呢?我們可以先列出所有可能的兩位數(shù),然后判斷它們是否是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是2。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)兩位數(shù)是15。因?yàn)?和5都是質(zhì)數(shù),且3×5=15,而5減去3就是2,所以15是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是2。二、填空題(本大題共10小題,每小題3分,共30分。請(qǐng)將答案填寫在答題卡相應(yīng)位置。)1.有一個(gè)自然數(shù),它除以3余1,除以4余2,除以5余3,那么這個(gè)自然數(shù)最小是多少呢?我們可以用逐步增加的方法來(lái)解。首先,找到一個(gè)滿足除以3余1的自然數(shù),比如1,然后逐漸增加3,得到1,4,7,10,13,16,19,22,25,28,31,34,37,40,43,46,49,52,55,58,61,64,67,70,73,76,79,82,85,88,91,94,97,100,103,106,109,112,115,118,121,124,127,130,133,136,139,142,145,148,151,154,157,160,163,166,169,172,175,178,181,184,187,190,193,196,199,202,205,208,211,214,217,220,223,226,229,232,235,238,241,244,247,250,253,256,259,262,265,268,271,274,277,280,283,286,289,292,295,298,301,304,307,310,313,316,319,322,325,328,331,334,337,340,343,346,349,352,355,358,361,364,367,370,373,376,379,382,385,388,391,394,397,400,403,406,409,412,415,418,421,424,427,430,433,436,439,442,445,448,451,454,457,460,463,466,469,472,475,478,481,484,487,490,493,496,499,502,505,508,511,514,517,520,523,526,529,532,535,538,541,544,547,550,553,556,559,562,565,568,571,574,577,580,583,586,589,592,595,598,601,604,607,610,613,616,619,622,625,628,631,634,637,640,643,646,649,652,655,658,661,664,667,670,673,676,679,682,685,688,691,694,697,700,703,706,709,712,715,718,721,724,727,730,733,736,739,742,745,748,751,754,757,760,763,766,769,772,775,778,781,784,787,790,793,796,799,802,805,808,811,814,817,820,823,826,829,832,835,838,841,844,847,850,853,856,859,862,865,868,871,874,877,880,883,886,889,892,895,898,901,904,907,910,913,916,919,922,925,928,931,934,937,940,943,946,949,952,955,958,961,964,967,970,973,976,979,982,985,988,991,994,997,1000。但是,這個(gè)數(shù)太大了,我們需要找到一個(gè)更小的數(shù)。我們可以嘗試從200開始,逐漸增加,直到找到一個(gè)滿足所有條件的最小自然數(shù)。經(jīng)過(guò)嘗試,我們發(fā)現(xiàn)這個(gè)自然數(shù)是59。所以,這個(gè)自然數(shù)最小是59。三、解答題(本大題共5小題,每小題6分,共30分。請(qǐng)將解答過(guò)程寫在答題卡相應(yīng)位置。)1.有一個(gè)兩位數(shù),它是兩個(gè)質(zhì)數(shù)的和,且這兩個(gè)質(zhì)數(shù)的差是3,那么這個(gè)兩位數(shù)是多少呢?我們可以先列出所有可能的兩位數(shù),然后判斷它們是否是兩個(gè)質(zhì)數(shù)的和,且這兩個(gè)質(zhì)數(shù)的差是3。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)兩位數(shù)是10。因?yàn)?和7都是質(zhì)數(shù),且3+7=10,而7減去3就是3,所以10是兩個(gè)質(zhì)數(shù)的和,且這兩個(gè)質(zhì)數(shù)的差是3。2.有一個(gè)三位數(shù),它的個(gè)位數(shù)字比十位數(shù)字大4,比百位數(shù)字大6,這個(gè)三位數(shù)是三個(gè)連續(xù)質(zhì)數(shù)之和,那么這個(gè)三位數(shù)是多少呢?我們可以先設(shè)個(gè)位數(shù)字為x,那么十位數(shù)字就是x-4,百位數(shù)字就是x-6。因?yàn)檫@是一個(gè)三位數(shù),所以百位數(shù)字不能為0,所以x-6必須大于0。又因?yàn)閭€(gè)位數(shù)字最大是9,所以x必須小于等于9。我們可以列出所有可能的兩位數(shù),然后判斷它們是否是三個(gè)連續(xù)質(zhì)數(shù)之和。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)三位數(shù)是238。因?yàn)?,3,5都是質(zhì)數(shù),且2+3+5=10,而10減去2就是8,所以238是三個(gè)連續(xù)質(zhì)數(shù)之和。3.有一個(gè)自然數(shù),它除以4余1,除以5余2,除以6余3,那么這個(gè)自然數(shù)最小是多少呢?這道題其實(shí)和同余方程有關(guān),我們可以用逐步增加的方法來(lái)解。首先,找到一個(gè)滿足除以4余1的自然數(shù),比如1,然后逐漸增加4,得到1,5,9,13,17,21,25,29,33,37,41,45,49,53,57,61,65,69,73,77,81,85,89,93,97,101,105,109,113,117,121,125,129,133,137,141,145,149,153,157,161,165,169,173,177,181,185,189,193,197,201,205,209,213,217,221,225,229,233,237,241,245,249,253,257,261,265,269,273,277,281,285,289,293,297,301,305,309,313,317,321,325,329,333,337,341,345,349,353,357,361,365,369,373,377,381,385,389,393,397,401,405,409,413,417,421,425,429,433,437,441,445,449,453,457,461,465,469,473,477,481,485,489,493,497,501,505,509,513,517,521,525,529,533,537,541,545,549,553,557,561,565,569,573,577,581,585,589,593,597,601,605,609,613,617,621,625,629,633,637,641,645,649,653,657,661,665,669,673,677,681,685,689,693,697,701,705,709,713,717,721,725,729,733,737,741,745,749,753,757,761,765,769,773,777,781,785,789,793,797,801,805,809,813,817,821,825,829,833,837,841,845,849,853,857,861,865,869,873,877,881,885,889,893,897,901,905,909,913,917,921,925,929,933,937,941,945,949,953,957,961,965,969,973,977,981,985,989,993,997,1000。但是,這個(gè)數(shù)太大了,我們需要找到一個(gè)更小的數(shù)。我們可以嘗試從200開始,逐漸增加,直到找到一個(gè)滿足所有條件的最小自然數(shù)。經(jīng)過(guò)嘗試,我們發(fā)現(xiàn)這個(gè)自然數(shù)是59。所以,這個(gè)自然數(shù)最小是59。4.有一個(gè)兩位數(shù),它是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是4,那么這個(gè)兩位數(shù)是多少呢?我們可以先列出所有可能的兩位數(shù),然后判斷它們是否是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是4。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)兩位數(shù)是15。因?yàn)?和5都是質(zhì)數(shù),且3×5=15,而5減去3就是4,所以15是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是4。5.有一個(gè)三位數(shù),它的個(gè)位數(shù)字比十位數(shù)字大2,比百位數(shù)字大4,這個(gè)三位數(shù)是三個(gè)連續(xù)質(zhì)數(shù)之和,那么這個(gè)三位數(shù)是多少呢?我們可以先設(shè)個(gè)位數(shù)字為x,那么十位數(shù)字就是x-2,百位數(shù)字就是x-4。因?yàn)檫@是一個(gè)三位數(shù),所以百位數(shù)字不能為0,所以x-4必須大于0。又因?yàn)閭€(gè)位數(shù)字最大是9,所以x必須小于等于9。我們可以列出所有可能的兩位數(shù),然后判斷它們是否是三個(gè)連續(xù)質(zhì)數(shù)之和。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)三位數(shù)是238。因?yàn)?,3,5都是質(zhì)數(shù),且2+3+5=10,而10減去2就是8,所以238是三個(gè)連續(xù)質(zhì)數(shù)之和。四、應(yīng)用題(本大題共5小題,每小題6分,共30分。請(qǐng)將解答過(guò)程寫在答題卡相應(yīng)位置。)1.有一個(gè)自然數(shù),它除以3余1,除以5余2,除以7余3,那么這個(gè)自然數(shù)最小是多少呢?我們可以用逐步增加的方法來(lái)解。首先,找到一個(gè)滿足除以3余1的自然數(shù),比如1,然后逐漸增加3,得到1,4,7,10,13,16,19,22,25,28,31,34,37,40,43,46,49,52,55,58,61,64,67,70,73,76,79,82,85,88,91,94,97,100,103,106,109,112,115,118,121,124,127,130,133,136,139,142,145,148,151,154,157,160,163,166,169,172,175,178,181,184,187,190,193,196,199,202,205,208,211,214,217,220,223,226,229,232,235,238,241,244,247,250,253,256,259,262,265,268,271,274,277,280,283,286,289,292,295,298,301,304,307,310,313,316,319,322,325,328,331,334,337,340,343,346,349,352,355,358,361,364,367,370,373,376,379,382,385,388,391,394,397,400,403,406,409,412,415,418,421,424,427,430,433,436,439,442,445,448,451,454,457,460,463,466,469,472,475,478,481,484,487,490,493,496,499,502,505,508,511,514,517,520,523,526,529,532,535,538,541,544,547,550,553,556,559,562,565,568,571,574,577,580,583,586,589,592,595,598,601,604,607,610,613,616,619,622,625,628,631,634,637,640,643,646,649,652,655,658,661,664,667,670,673,676,679,682,685,688,691,694,697,700,703,706,709,712,715,718,721,724,727,730,733,736,739,742,745,748,751,754,757,760,763,766,769,772,775,778,781,784,787,790,793,796,799,802,805,808,811,814,817,820,823,826,829,832,835,838,841,844,847,850,853,856,859,862,865,868,871,874,877,880,883,886,889,892,895,898,901,904,907,910,913,916,919,922,925,928,931,934,937,940,943,946,949,952,955,958,961,964,967,970,973,976,979,982,985,988,991,994,997,1000。但是,這個(gè)數(shù)太大了,我們需要找到一個(gè)更小的數(shù)。我們可以嘗試從200開始,逐漸增加,直到找到一個(gè)滿足所有條件的最小自然數(shù)。經(jīng)過(guò)嘗試,我們發(fā)現(xiàn)這個(gè)自然數(shù)是59。所以,這個(gè)自然數(shù)最小是59。2.有一個(gè)兩位數(shù),它是兩個(gè)質(zhì)數(shù)的和,且這兩個(gè)質(zhì)數(shù)的差是3,那么這個(gè)兩位數(shù)是多少呢?我們可以先列出所有可能的兩位數(shù),然后判斷它們是否是兩個(gè)質(zhì)數(shù)的和,且這兩個(gè)質(zhì)數(shù)的差是3。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)兩位數(shù)是10。因?yàn)?和7都是質(zhì)數(shù),且3+7=10,而7減去3就是3,所以10是兩個(gè)質(zhì)數(shù)的和,且這兩個(gè)質(zhì)數(shù)的差是3。3.有一個(gè)三位數(shù),它的個(gè)位數(shù)字比十位數(shù)字大4,比百位數(shù)字大6,這個(gè)三位數(shù)是三個(gè)連續(xù)質(zhì)數(shù)之和,那么這個(gè)三位數(shù)是多少呢?我們可以先設(shè)個(gè)位數(shù)字為x,那么十位數(shù)字就是x-4,百位數(shù)字就是x-6。因?yàn)檫@是一個(gè)三位數(shù),所以百位數(shù)字不能為0,所以x-6必須大于0。又因?yàn)閭€(gè)位數(shù)字最大是9,所以x必須小于等于9。我們可以列出所有可能的兩位數(shù),然后判斷它們是否是三個(gè)連續(xù)質(zhì)數(shù)之和。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)三位數(shù)是238。因?yàn)?,3,5都是質(zhì)數(shù),且2+3+5=10,而10減去2就是8,所以238是三個(gè)連續(xù)質(zhì)數(shù)之和。4.有一個(gè)兩位數(shù),它是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是4,那么這個(gè)兩位數(shù)是多少呢?我們可以先列出所有可能的兩位數(shù),然后判斷它們是否是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是4。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)兩位數(shù)是15。因?yàn)?和5都是質(zhì)數(shù),且3×5=15,而5減去3就是4,所以15是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是4。5.有一個(gè)三位數(shù),它的個(gè)位數(shù)字比十位數(shù)字大2,比百位數(shù)字大4,這個(gè)三位數(shù)是三個(gè)連續(xù)質(zhì)數(shù)之和,那么這個(gè)三位數(shù)是多少呢?我們可以先設(shè)個(gè)位數(shù)字為x,那么十位數(shù)字就是x-2,百位數(shù)字就是x-4。因?yàn)檫@是一個(gè)三位數(shù),所以百位數(shù)字不能為0,所以x-4必須大于0。又因?yàn)閭€(gè)位數(shù)字最大是9,所以x必須小于等于9。我們可以列出所有可能的兩位數(shù),然后判斷它們是否是三個(gè)連續(xù)質(zhì)數(shù)之和。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)三位數(shù)是238。因?yàn)?,3,5都是質(zhì)數(shù),且2+3+5=10,而10減去2就是8,所以238是三個(gè)連續(xù)質(zhì)數(shù)之和。五、綜合題(本大題共5小題,每小題6分,共30分。請(qǐng)將解答過(guò)程寫在答題卡相應(yīng)位置。)1.有一個(gè)自然數(shù),它除以3余1,除以5余2,除以7余3,那么這個(gè)自然數(shù)最小是多少呢?我們可以用逐步增加的方法來(lái)解。首先,找到一個(gè)滿足除以3余1的自然數(shù),比如1,然后逐漸增加3,得到1,4,7,10,13,16,19,22,25,28,31,34,37,40,43,46,49,52,55,58,61,64,67,70,73,76,79,82,85,88,91,94,97,100,103,106,109,112,115,118,121,124,127,130,133,136,139,142,145,148,151,154,157,160,163,166,169,172,175,178,181,184,187,190,193,196,199,202,205,208,211,214,217,220,223,226,229,232,235,238,241,244,247,250,253,256,259,262,265,268,271,274,277,280,283,286,289,292,295,298,301,304,307,310,313,316,319,322,325,328,331,334,337,340,343,346,349,352,355,358,361,364,367,370,373,376,379,382,385,388,391,394,397,400,403,406,409,412,415,418,421,424,427,430,433,436,439,442,445,448,451,454,457,460,463,466,469,472,475,478,481,484,487,490,493,496,499,502,505,508,511,514,517,520,523,526,529,532,535,538,541,544,547,550,553,556,559,562,565,568,571,574,577,580,583,586,589,592,595,598,601,604,607,610,613,616,619,622,625,628,631,634,637,640,643,646,649,652,655,658,661,664,667,670,673,676,679,682,685,688,691,694,697,700,703,706,709,712,715,718,721,724,727,730,733,736,739,742,745,748,751,754,757,760,763,766,769,772,775,778,781,784,787,790,793,796,799,802,805,808,811,814,817,820,823,826,829,832,835,838,841,844,847,850,853,856,859,862,865,868,871,874,877,880,883,886,889,892,895,898,901,904,907,910,913,916,919,922,925,928,931,934,937,940,943,946,949,952,955,958,961,964,967,970,973,976,979,982,985,988,991,994,997,1000。但是,這個(gè)數(shù)太大了,我們需要找到一個(gè)更小的數(shù)。我們可以嘗試從200開始,逐漸增加,直到找到一個(gè)滿足所有條件的最小自然數(shù)。經(jīng)過(guò)嘗試,我們發(fā)現(xiàn)這個(gè)自然數(shù)是59。所以,這個(gè)自然數(shù)最小是59。2.有一個(gè)兩位數(shù),它是兩個(gè)質(zhì)數(shù)的和,且這兩個(gè)質(zhì)數(shù)的差是3,那么這個(gè)兩位數(shù)是多少呢?我們可以先列出所有可能的兩位數(shù),然后判斷它們是否是兩個(gè)質(zhì)數(shù)的和,且這兩個(gè)質(zhì)數(shù)的差是3。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)兩位數(shù)是10。因?yàn)?和7都是質(zhì)數(shù),且3+7=10,而7減去3就是3,所以10是兩個(gè)質(zhì)數(shù)的和,且這兩個(gè)質(zhì)數(shù)的差是3。3.有一個(gè)三位數(shù),它的個(gè)位數(shù)字比十位數(shù)字大4,比百位數(shù)字大6,這個(gè)三位數(shù)是三個(gè)連續(xù)質(zhì)數(shù)之和,那么這個(gè)三位數(shù)是多少呢?我們可以先設(shè)個(gè)位數(shù)字為x,那么十位數(shù)字就是x-4,百位數(shù)字就是x-6。因?yàn)檫@是一個(gè)三位數(shù),所以百位數(shù)字不能為0,所以x-6必須大于0。又因?yàn)閭€(gè)位數(shù)字最大是9,所以x必須小于等于9。我們可以列出所有可能的兩位數(shù),然后判斷它們是否是三個(gè)連續(xù)質(zhì)數(shù)之和。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)三位數(shù)是238。因?yàn)?,3,5都是質(zhì)數(shù),且2+3+5=10,而10減去2就是8,所以238是三個(gè)連續(xù)質(zhì)數(shù)之和。4.有一個(gè)兩位數(shù),它是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是4,那么這個(gè)兩位數(shù)是多少呢?我們可以先列出所有可能的兩位數(shù),然后判斷它們是否是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是4。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)兩位數(shù)是15。因?yàn)?和5都是質(zhì)數(shù),且3×5=15,而5減去3就是4,所以15是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是4。5.有一個(gè)三位數(shù),它的個(gè)位數(shù)字比十位數(shù)字大2,比百位數(shù)字大4,這個(gè)三位數(shù)是三個(gè)連續(xù)質(zhì)數(shù)之和,那么這個(gè)三位數(shù)是多少呢?我們可以先設(shè)個(gè)位數(shù)字為x,那么十位數(shù)字就是x-2,百位數(shù)字就是x-4。因?yàn)檫@是一個(gè)三位數(shù),所以百位數(shù)字不能為0,所以x-4必須大于0。又因?yàn)閭€(gè)位數(shù)字最大是9,所以x必須小于等于9。我們可以列出所有可能的兩位數(shù),然后判斷它們是否是三個(gè)連續(xù)質(zhì)數(shù)之和。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)三位數(shù)是238。因?yàn)?,3,5都是質(zhì)數(shù),且2+3+5=10,而10減去2就是8,所以238是三個(gè)連續(xù)質(zhì)數(shù)之和。本次試卷答案如下:一、選擇題1.答案:10解析:因?yàn)?和5都是質(zhì)數(shù),且3+5=10,而5減去3就是2,所以10是兩個(gè)質(zhì)數(shù)的和,且這兩個(gè)質(zhì)數(shù)的差是2。2.答案:238解析:因?yàn)?,3,5都是質(zhì)數(shù),且2+3+5=10,而10減去2就是8,所以238是三個(gè)連續(xù)質(zhì)數(shù)之和。3.答案:15解析:因?yàn)?和5都是質(zhì)數(shù),且3×5=15,而5減去3就是2,所以15是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是2。4.答案:10解析:因?yàn)?和7都是質(zhì)數(shù),且3+7=10,而7減去3就是4,所以10是兩個(gè)質(zhì)數(shù)的和,且這兩個(gè)質(zhì)數(shù)的差是4。5.答案:238解析:因?yàn)?,3,5都是質(zhì)數(shù),且2+3+5=10,而10減去2就是8,所以238是三個(gè)連續(xù)質(zhì)數(shù)之和。二、填空題1.答案:59解析:我們可以用逐步增加的方法來(lái)解。首先,找到一個(gè)滿足除以3余1的自然數(shù),比如1,然后逐漸增加3,得到1,4,7,10,13,16,19,22,25,28,31,34,37,40,43,46,49,52,55,58,61,64,67,70,73,76,79,82,85,88,91,94,97,100,103,106,109,112,115,118,121,124,127,130,133,136,139,142,145,148,151,154,157,160,163,166,169,172,175,178,181,184,187,190,193,196,199,202,205,208,211,214,217,220,223,226,229,232,235,238,241,244,247,250,253,256,259,262,265,268,271,274,277,280,283,286,289,292,295,298,301,304,307,310,313,316,319,322,325,328,331,334,337,340,343,346,349,352,355,358,361,364,367,370,373,376,379,382,385,388,391,394,397,400,403,406,409,412,415,418,421,424,427,430,433,436,439,442,445,448,451,454,457,460,463,466,469,472,475,478,481,484,487,490,493,496,499,502,505,508,511,514,517,520,523,526,529,532,535,538,541,544,547,550,553,556,559,562,565,568,571,574,577,580,583,586,589,592,595,598,601,604,607,610,613,616,619,622,625,628,631,634,637,640,643,646,649,652,655,658,661,664,667,670,673,676,679,682,685,688,691,694,697,700,703,706,709,712,715,718,721,724,727,730,733,736,739,742,745,748,751,754,757,760,763,766,769,772,775,778,781,784,787,790,793,796,799,802,805,808,811,814,817,820,823,826,829,832,835,838,841,844,847,850,853,856,859,862,865,868,871,874,877,880,883,886,889,892,895,898,901,904,907,910,913,916,919,922,925,928,931,934,937,940,943,946,949,952,955,958,961,964,967,970,973,976,979,982,985,988,991,994,997,1000。但是,這個(gè)數(shù)太大了,我們需要找到一個(gè)更小的數(shù)。我們可以嘗試從200開始,逐漸增加,直到找到一個(gè)滿足所有條件的最小自然數(shù)。經(jīng)過(guò)嘗試,我們發(fā)現(xiàn)這個(gè)自然數(shù)是59。所以,這個(gè)自然數(shù)最小是59。3.答案:238解析:因?yàn)?,3,5都是質(zhì)數(shù),且2+3+5=10,而10減去2就是8,所以238是三個(gè)連續(xù)質(zhì)數(shù)之和。4.答案:15解析:因?yàn)?和5都是質(zhì)數(shù),且3×5=15,而5減去3就是2,所以15是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是2。5.答案:238解析:因?yàn)?,3,5都是質(zhì)數(shù),且2+3+5=10,而10減去2就是8,所以233是三個(gè)連續(xù)質(zhì)數(shù)之和。三、解答題1.答案:59解析:我們可以用逐步增加的方法來(lái)解。首先,找到一個(gè)滿足除以3余1的自然數(shù),比如1,然后逐漸增加3,得到1,4,7,10,13,16,19,22,25,28,31,34,37,40,43,46,49,52,55,58,61,64,67,70,73,76,79,82,85,88,91,94,97,100,103,106,109,112,115,118,121,124,127,130,133,136,139,142,145,148,151,154,157,160,163,166,169,172,175,178,181,184,187,190,193,196,199,202,205,208,211,214,217,220,223,226,229,232,235,238,241,244,247,250,253,256,259,262,265,268,271,274,277,280,283,286,289,292,295,298,301,304,307,310,313,316,319,322,325,328,331,334,337,340,343,346,349,352,355,358,361,364,367,370,373,376,379,382,385,388,391,394,397,400,403,406,409,412,415,418,421,424,427,430,843,343。但是,這個(gè)數(shù)太大了,我們需要找到一個(gè)更小的數(shù)。我們可以嘗試從200開始,逐漸增加,直到找到一個(gè)滿足所有條件的最小自然數(shù)。經(jīng)過(guò)嘗試,我們發(fā)現(xiàn)這個(gè)自然數(shù)是59。所以,這個(gè)自然數(shù)最小是59。2.答案:238解析:有一個(gè)三位數(shù),它的個(gè)位數(shù)字比十位數(shù)字大4,比百位數(shù)字大6,這個(gè)三位數(shù)是三個(gè)連續(xù)質(zhì)數(shù)之和,那么這個(gè)三位數(shù)是多少呢?我們可以先設(shè)個(gè)位數(shù)字為x,那么十位數(shù)字就是x-4,百位數(shù)字就是x-6。因?yàn)檫@是一個(gè)三位數(shù),所以百位數(shù)字不能為0,所以x-6必須大于0。又因?yàn)閭€(gè)位數(shù)字最大是9,所以x必須小于等于9。我們可以列出所有可能的兩位數(shù),然后判斷它們是否是三個(gè)連續(xù)質(zhì)數(shù)之和。通過(guò)列舉和判斷,我們發(fā)現(xiàn)這個(gè)三位數(shù)是238。因?yàn)?,3,5都是質(zhì)數(shù),且2+3+5=10,而10減去2就是8,所以238是三個(gè)連續(xù)質(zhì)數(shù)之和。3.答案:15解析:有一個(gè)兩位數(shù),它是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)數(shù)的差是4,那么這個(gè)兩位數(shù)是多少呢?我們可以先列出所有可能的兩位數(shù),然后判斷它們是否是兩個(gè)質(zhì)數(shù)的乘積,且這兩個(gè)質(zhì)
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