I found an answer from www.quora.com

Couldn't we take the product **of all prime numbers** and **add 1** to find ...

Jul 25, 2016 **...** A product **of primes plus 1** is still **not** necessarily **prime**, as is **not prime** ... **prime**
just proves that you weren't multiplying **all the primes together** in ...

For more information, see Couldn't we take the product **of all prime numbers** and **add 1** to find ...

I found an answer from www.bbc.com

Multiples, **factors**, powers and roots - OCR - Revision 2 - GCSE ...

Learn about and revise different types **of** numbers such as **primes**, factors,
multiples and powers with ... **1** is **not** a **prime number** as it only has **one** factor -
itself.

For more information, see Multiples, **factors**, powers and roots - OCR - Revision 2 - GCSE ...

I found an answer from www.britannica.com

Arithmetic | Britannica.com

Mar 12, 2019 **...** Arithmetic: Arithmetic, branch **of** mathematics in which numbers, ... The operation
**of** forming the sum is called addition, the symbol + being read as “**plus**. .... A
positive integer neither **1** nor **composite** is called a **prime number**. Thus ... Then
the GCD is obtained by multiplying **together each prime** that occurs in ...

For more information, see Arithmetic | Britannica.com

I found an answer from www.smithsonianmag.com

The Great Debate Over Whether **1**+2+3+4..+ ∞ = -**1**/12 | Smart News

Jan 31, 2014 **...** Can the sum **of all** positive integers = -**1**/12? ... Your browser does **not** currently
recognize any **of** the video formats available. ... You can **add** an infinite series **of**
positive **numbers**, and they'll **add up** to a negative fraction,” said ...

For more information, see The Great Debate Over Whether **1**+2+3+4..+ ∞ = -**1**/12 | Smart News

I found an answer from www.khanacademy.com

Finding common denominators (video) | Khan Academy

**If** you look hard they **all** have or are equal to the **number** 12. I hope my answer ...
Then, your common denominator is the denominator that is **not 1**. For example: ...

For more information, see Finding common denominators (video) | Khan Academy

I found an answer from en.wikipedia.org

**Prime number** - Wikipedia

A **prime number** (or a **prime**) is a natural number greater than **1** that cannot be
formed by multiplying two smaller natural numbers. A natural number greater
than **1** that is **not prime** is called a **composite** number. For example, 5 is **prime**
because the only ways **of** writing it as a product, **1** ..... The numbers formed by
**adding one** to the products **of** the smallest **primes** ...

For more information, see **Prime number** - Wikipedia

I found an answer from math.stackexchange.com

Why is it that the product **of** first N **prime numbers** + **1** another **prime** ...

It is **not** necessarily another **prime**, but it is most definitely divisible by ... It cannot
be divisible by any **one of** those first N **primes**, so it has to be ...

For more information, see Why is it that the product **of** first N **prime numbers** + **1** another **prime** ...

I found an answer from stackoverflow.com

Why do we check **up** to the square root **of** a **prime number** to ...

So **if** a **number** (greater than **1**) is **not prime** and we test divisibility **up** to ... And we
also know that ai <= sqrt(N) and thus you need to check till sqrt(N) which will
cover **all** ai. .... Reductio **ad** absurdum; n's smallest factor must be LTE sqrt n.

For more information, see Why do we check **up** to the square root **of** a **prime number** to ...