Show that there are no prime numbers from 200 to 210?

Answer 1

There are 2 prime numbers, they are 201 and 203

_____________________________

No.

201 is divisible by three: 3 x 67 = 201

203 is divisible by seven: 7 x 29 = 203

To show a number (n) is prime, you must show it is not divisible by any prime up to the square root of n.

Any even number is divisible by two; any number ending in 5 is divisible by five. So you only have to check the numbers ending in 1, 3, 7, or 9.

201 and 207 are divisible by three. Any easy check is to add the digits. If that total is divisible by three, so is the original number. That rules out 201 and 207.

203 is divisible by seven. Any easy (but not well known) test for divisibility by seven is this. Take the ones digit, double it, subtract from the remaining digits. In this case, for 203, take 3, double it to 6, and subtract from 20 to get 14. 14 is divisible by seven, so the original 203 is as well.

209 is divisible by eleven. A test for elevens is to add every other digit to get one total, add the other digits to get a second total, then take the difference of those totals. 2 + 9 = 11 for the first total. 0 is the other total. 11 - 0 = 11 and that is divisible by eleven.

Answer 2

200 and 205 is divisible by

clearly 5️⃣

201 and 207 are both divisible by 3️⃣

202, 204, 206, 208 and 210 are all divisible by 2️⃣

203 is divisible by 7️⃣ (20-3*2=14 and 14 is divisible by 7)

And finally, 209 is divisible by 11 [(2+9)-0=11 and 11 is divisible by 11]

Answer 3

There just aren’t

Answer 4

because there is non

Answer 5

Because there not

Answer 6

Gjm

Answer 7

在艰苦中成长成功之人，往往由于心理的阴影，会导致变态的偏差，这种偏差，便是对社会、对人们始终有一种仇视的敌意，不相信任何一个人，更不同情任何一个人。爱钱如命的悭吝，还是心理变态上的次要现象。相反地，有器度，有见识的人，他虽然从艰苦困难中成长，反而更具有同情心和慷慨好义的胸襟怀抱。因为他懂得人生，知道世情的甘苦。

苏秦是豪杰之士，所以他在憬悟到人生的正面和反面，人性的美好和众生相的丑陋以后，便慨然拿出千金，普遍散赐给宗族和朋友们。同时还报过去穷困时对他有恩惠的人。当他第二次出门到北方去的时候，有一位乡邻，借给他一百钱做路费，他便加十倍的回报，还了他百两黄金。这种举动，看起来、说起来很容易，事实上，到了自己头上，要痛痛快快、慷慷慨慨地做起来，就真不容易。还有太多的事例，在此不多作讨论。

原文中接下去，另一小节的记载，很好笑。当苏秦在家乡正做这样豪举的时候，有一个乡亲是当年跟他到北方燕国去的，可是苏秦这次却对他没有什么表示。这个人干干脆脆，自己直接向苏秦说，我跟你没有功劳，也总有些苦劳，为什么你不给我一点好处呢？苏秦说，对不起，其实我没有忘了你，只是你太过份了，当我在艰苦的时候，很需要你跟着我，帮忙我到燕国去，可是你看我当时在赵国没有什么成就，所以在我渡过易水要到燕国去的最困难关键上，你再三想离开我，不肯再帮我了。你要知道，在那个时候，正是我困难得要命的时候，多么希望得到你的帮助和鼓励。可是你却很势利，真让我痛心极了。所以现在我故意把要给你的一份摆在最后，也是给你一点教训的意思。好了，你现在又当面来要求，当然有，这一份便是我为你准备的，现在你拿去吧！

在《史记》里，司马迁写《苏秦列传》，把这样一件小事也记载上去，这正如现代的我们写白话传记一样，在一件小事上，一个小动作上，特别加以叙述，此中往往衬托出很重要的观念，要读者好好去思辨，好好去体会。——《孟子旁通》

Answer 8

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 9

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Answer 10

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