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More about usAn interesting math shortcut prime number trick. By using this math trick we are able to find a large number "A" is prime number or not just in 30 seconds. (In this Math Shortcut tricks we use a square root method)

Before starting this math shortcuts prime number trick i suggest that you should understand the basic prime number defination and studied other basic prime number shortcut tricks avaliabe are below of this shortcut trick.

Take a list of prime no. less then the sq root (A). Now check the number A is divisible by any of prime number list or not. If number A is divisible by any number of prime number less then sq. root(A). Then the number A is prime number other wise it will be composite number.

Let us apply this amazing Math Prime number shortcut tricks on following examples.

The square root of 313 is 17.69... (Approximately 18) The prime number less than 18 are 2, 3, 5, 7, 11, 13, 17.

Because 313 is not divisible by any of them. Therefore 313 is a prime number.

The square root of 881 is approximately 30. The prime numbers less than 30 are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29.

Because 881 is not divisible by any of the above numbers. Therefore, 881 is a prime number.

The square root of 2329 is approximately 48.26. The prime numbers less than 48.26 are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47

Because 2329 is divisible 17. Therefore, 2329 is not prime number.

The square root of 3841 is approximately 62.

The prime numbers less than 62 are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61.

Now we check that the number 3841 is divisible by any of the above number or not. During keep testing we found 3841 is completly divisible by 23 becauuse 23*167=3841.

Therefore 3841 is not prime number.

The square root of 994009 is approximately 997.

The prime numbers less than 997 are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467,479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991,997

Now we check that the number 994009 is divisible by any of the above number or not (we can use calculator for this checking). During keep testing we found is completly divisible by 997 because 997 * 997 = 994009.

Therefore 3841 is not prime number.

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