769 and Level 2

  • 769 is a prime number.
  • Prime factorization: 769 is prime.
  • The exponent of prime number 769 is 1. Adding 1 to that exponent we get (1 + 1) = 2. Therefore 769 has exactly 2 factors.
  • Factors of 769: 1, 769
  • Factor pairs: 769 = 1 x 769
  • 769 has no square factors that allow its square root to be simplified. √769 ≈ 27.730849.

769-factor-pairs

How do we know that 769 is a prime number? If 769 were not a prime number, then it would be divisible by at least one prime number less than or equal to √769 ≈ 27.7. Since 769 cannot be divided evenly by 2, 3, 5, 7, 11, 13, 17, 19, or 23, we know that 769 is a prime number.

Here is today’s puzzle:

 

769 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2016-02-25

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Here’s more about prime number 769:

25² + 12² = 769, and 769 is the hypotenuse of primitive Pythagorean triple 481-600-769 which was calculated from 25² – 12², 2(25)(12), 25² + 12².

Thus 481² + 600² = 769².

769 is also the sum of three squares five different ways.

  • 27² + 6² + 2² = 769
  • 24² + 12² + 7² = 769
  • 21² + 18² + 2² = 769
  • 20² + 15² + 12² = 769
  • 18² + 18² + 11² = 769

769 is palindrome 181 in BASE 24; note that 1(24²) + 8(24) + 1(1) = 769.

Here’s another way we know that 769 is a prime number: Since  its last two digits divided by 4 leave a remainder of 1, and 25² + 12² = 769 with 25 and 12 having no common prime factors, 769 will be prime unless it is divisible by a prime number Pythagorean hypotenuse less than or equal to √769 ≈ 27.7. Since 769 is not divisible by 5, 13, or 17, we know that 769 is a prime number.

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769 Factors


762 and Level 2

  • 762 is a composite number.
  • Prime factorization: 762 = 2 x 3 x 127
  • The exponents in the prime factorization are 1, 1, and 1. Adding one to each and multiplying we get (1 + 1)(1 + 1)(1 + 1) = 2 x 2 x 2 = 8. Therefore 762 has exactly 8 factors.
  • Factors of 762: 1, 2, 3, 6, 127, 254, 381, 762
  • Factor pairs: 762 = 1 x 762, 2 x 381, 3 x 254, or 6 x 127
  • 762 has no square factors that allow its square root to be simplified. √762 ≈ 27.604347.

762-factor-pairs

This level 2 puzzle isn’t very difficult:

 

762 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2016-02-04

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Here’s a little more about the number 762:

People who memorize the digits of pi have to stop someplace. Wikipedia informs us that one place to stop is known as the Feynman point which is 999999 beginning at pi’s 762nd decimal place. It is named after Richard Feynman who reportedly said in a lecture that he would like to recite from memory the digits of pi up to that point because he could then end the recitation by saying 999999 and so on. Perhaps he would even be able to make pi sound like a rational number? Be sure to check out the highlighted digits of both pi and tau that appear in a graphic in that article. There is also an explanation of how truly unusual a sequence of six repeating digits can be.

762 can be written as the sum of consecutive numbers three ways:

  • 253 + 254 + 255 = 762; that’s 3 consecutive numbers. (254 × 3 = 762)
  • 189 + 190 + 191 + 192 = 762; that’s 4 consecutive numbers.
  • 58 + 59 + 60 + 61 + 62 + 63 + 64 + 65 + 66 + 67 + 68 + 69  = 762; that’s 12 consecutive numbers.

762 can also be written as the sum of two consecutive prime numbers: 379 + 383 = 762, and as the sum of four consecutive prime numbers: 181 + 191 + 193 + 197 = 762.

762 is the sum of three squares three different ways:

  • 25² + 11² + 4² = 762
  • 23² + 13² + 8² = 762
  • 20² + 19² + 1² = 762

762 is palindrome and repdigit 222 in BASE 19 because 2(19²) + 2(19) + 2(1) = 762.

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762 Factors

755 and Level 2

  • 755 is a composite number.
  • Prime factorization: 755 = 5 x 151
  • The exponents in the prime factorization are 1 and 1. Adding one to each and multiplying we get (1 + 1)(1 + 1) = 2 x 2 = 4. Therefore 755 has exactly 4 factors.
  • Factors of 755: 1, 5, 151, 755
  • Factor pairs: 755 = 1 x 755 or 5 x 151
  • 755 has no square factors that allow its square root to be simplified. √755 ≈ 27.4772633.

755-factor-pairs

Here’s today’s puzzle:

 

755 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2016-01-25

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Here’s a little more about 755:

755 is the sum of consecutive numbers three different ways:

  • 377 + 378 = 755; that’s 2 consecutive numbers.
  • 149 + 150 + 151 + 152 + 153 = 755; that’s 5 consecutive numbers.
  • 71 + 72 + 73 + 74 + 75 + 76 + 77 + 78 + 79 + 80 = 755; that’s 10 consecutive numbers.

Because 5 is one of its factors, 755 is the hypotenuse of Pythagorean triple 453-604-755.

755 is the sum of three squares six different ways:

  • 27² + 5² + 1² = 755
  • 25² + 11² + 3² = 755
  • 25² + 9² + 7² = 755
  • 23² + 15² + 1² = 755
  • 21² + 17² + 5² = 755
  • 19² + 15² + 13² = 755

755 is palindrome 131 in BASE 26; note that 1(26²) + 3(26) + 1(1) = 755.

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755 Factors

748 and Level 2

  • 748 is a composite number.
  • Prime factorization: 748 = 2 x 2 x 11 x 17, which can be written 748 = (2^2) x 11 x 17
  • The exponents in the prime factorization are 2, 1, and 1. Adding one to each and multiplying we get (2 + 1)(1 + 1)(1 + 1) = 3 x 2 x 2 = 12. Therefore 748 has exactly 12 factors.
  • Factors of 748: 1, 2, 4, 11, 17, 22, 34, 44, 68, 187, 374, 748
  • Factor pairs: 748 = 1 x 748, 2 x 374, 4 x 187, 11 x 68, 17 x 44, or 22 x 34
  • Taking the factor pair with the largest square number factor, we get √748 = (√4)(√187) = 2√187 ≈ 27.34958866.

748-factor-pairs

Here is today’s puzzle:

748 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2016-01-18

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Here is some more about composite number 748:

748 can be written as the sum of consecutive numbers 3 ways:

  • 90 + 91 + 92 + 93 + 94 + 95 + 96 + 97 = 748; that’s 8 consecutive numbers.
  • 63 + 64 + 65 + 66 + 67 + 68 + 69 + 70 + 71 + 72 + 73 = 748; that’s 11 consecutive numbers.
  • 36 + 37 + 38 + 39 + 40 + 41 + 42 + 43 + 44 + 45 + 46 + 47 + 48 + 49 + 50 + 51 + 52 = 748; that’s 17 consecutive numbers.

Because 17 is one of its factors, 748 is the hypotenuse of Pythagorean triple 352-660-748, and 352² + 660² = 748².

748 is the sum of 3 squares two different ways. Both ways contain a duplicate square.

  • 26² + 6² + 6² = 748
  • 18² + 18² + 10² = 748

748 is palindrome MM in BASE 33 (M = 22 base 10); note that 22(33) + 22(1) = 748.

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748 Factors

740 and Level 2

  • 740 is a composite number.
  • Prime factorization: 740 = 2 x 2 x 5 x 37, which can be written 740 = (2^2) x 5 x 37
  • The exponents in the prime factorization are 2, 1, and 1. Adding one to each and multiplying we get (2 + 1)(1 + 1)(1 + 1) = 3 x 2 x 2 = 12. Therefore 740 has exactly 12 factors.
  • Factors of 740: 1, 2, 4, 5, 10, 20, 37, 74, 148, 185, 370, 740
  • Factor pairs: 740 = 1 x 740, 2 x 370, 4 x 185, 5 x 148, 10 x 74, or 20 x 37
  • Taking the factor pair with the largest square number factor, we get √740 = (√4)(√185) = 2√185 ≈ 27.202941.

740-factor-pairs

This level 2 puzzle isn’t too difficult to solve:

740 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2016-01-11

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Here’s more about 740:

740 is the sum of consecutive numbers several ways:

  • 146 + 147 + 148 + 149 + 150 = 740; that’s 5 consecutive numbers.
  • 89 + 90 + 91 + 92 + 93 + 94 + 95 + 96 = 740; that’s 8 consecutive numbers.
  • 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20 + 21 + 22 + 23 + 24 + 25 + 26 + 27 + 28 + 29 + 30 + 31 + 32 + 33 + 34 + 35 + 36 + 37 + 38 = 740; that’s 37 consecutive numbers.

Because 5 and 37 are two of its factors, 740 is the hypotenuse of four Pythagorean triples:

  • 240-700-740
  • 228-704-740
  • 416-612-740
  • 444-592-740

740 is also a palindrome in two bases, one of which is double the other:

  • 252 BASE 18; note that 2(18²) + 5(18) + 2(1) = 740.
  • KK BASE 36 (K = 20 base 10); note that 20(36) + 20(1)

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740 Factors

733 and Level 2

  • 733 is a prime number.
  • Prime factorization: 733 is prime.
  • The exponent of prime number 733 is 1. Adding 1 to that exponent we get (1 + 1) = 2. Therefore 733 has exactly 2 factors.
  • Factors of 733: 1, 733
  • Factor pairs: 733 = 1 x 733
  • 733 has no square factors that allow its square root to be simplified. √733 ≈ 27.0739727.

How do we know that 733 is a prime number? If 733 were not a prime number, then it would be divisible by at least one prime number less than or equal to √733 ≈ 27.1. Since 733 cannot be divided evenly by 2, 3, 5, 7, 11, 13, 17, 19, or 23, we know that 733 is a prime number.

Here’s another way we know that 733 is a prime number: Since  its last two digits divided by 4 leave a remainder of 1, and 17² + 2² = 733 with 17 and 2 having no common prime factors, 733 will be prime unless it is divisible by a prime number Pythagorean hypotenuse less than or equal to √733 ≈ 27.1. Since 733 is not divisible by 5, 13, or 17, we know that 733 is a prime number.

733-factor-pairs

Give this Level 2 factoring puzzle a try:

733 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2016-01-04

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Here are some more facts about the number 733:

733 is prime, so 366 + 367 = 733 is the only way it can be written as the sum of consecutive numbers.

733 is the sum of the prime numbers from 17 to 79. I think there’s a good chance you know what all those prime numbers are.

733 is also the sum of the five prime numbers from 137  to 157. You might not know what the missing primes are, but here’s a hint: If you subtract 100 from any of those three primes, you will get a composite number, and there are only three odd composite numbers that don’t end in 5 between 37 and 57.

27² + 2² = 733 so 733 is the hypotenuse of the (primitive) Pythagorean triple 108-725-733 which is calculated from 2(27)(2), 27² – 2², 27² + 2².

Thus, 108² + 725² = 733².

733 is palindrome 292 in BASE 17; note that 2(17²) + 9(17) + 2(1) = 733.

From Wikipedia I learned two other interesting facts about the number 733:

  • 727, 733, 739 are consecutive prime numbers whose average is 733.  That makes 733 the 13th balanced prime. It is exactly the same distance from the previous prime and the prime that follows it.
  • 337, 373, 733 are three of only nine 3-digit permutable prime numbers. No matter their order, those exact 3 digits produce a prime number.

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733 Factors

725 and Level 2

  • 725 is a composite number.
  • Prime factorization: 725 = 5 x 5 x 29, which can be written 725 = (5^2) x 29
  • The exponents in the prime factorization are 2 and 1. Adding one to each and multiplying we get (2 + 1)(1 + 1) = 3 x 2  = 6. Therefore 725 has exactly 6 factors.
  • Factors of 725: 1, 5, 25, 29, 145, 725
  • Factor pairs: 725 = 1 x 725, 5 x 145, or 25 x 29
  • Taking the factor pair with the largest square number factor, we get √725 = (√25)(√29) = 5√29 ≈ 26.925824.

Give this Level 2 puzzle a try!

725 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-12-28

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Perhaps, you would like to know some other facts about the number 725:

725 can be expressed as the sum of consecutive numbers five different ways:

  • 362 + 363 = 725; that’s 2 consecutive numbers.
  • 143 + 144 + 145 + 146 + 147 = 725; that’s 5 consecutive numbers.
  • 68 + 69 + 70 + 71 + 72 + 73 + 74 + 75 + 76 + 77 = 725; that’s 10 consecutive numbers.
  • 17 + 18 + 19 + . . . + 29 + . . . + 39 + 40 + 41 = 725; that’s 25 consecutive numbers.
  • 11 + 12 + 13 + . . . + 25 + . . . + 37 + 38 + 39 = 725; that’s 29 consecutive numbers.

725 is also the sum of the eleven prime numbers from 43 to 89.

The factors in one of its factor pairs, 25 x 29, are both 2 numbers away from their average, 27, so 725 is just 4 numbers away from perfect square 27² = 729 . Thus, 25 x 29 =  (27 – 2)(27 + 2) = 27² – 2² = 729 – 4 = 725.

725 is the sum of two squares three different ways:

  • 26² + 7² = 725
  • 25² + 10² = 725
  • 23² + 14² = 725

Because ALL of its prime factors have a remainder of one when divided by four, 725 is the hypotenuse of primitive Pythagorean triples:

  • 364-627-725 which was calculated using 2(26)(7), 26² – 7², 26² + 7²
  • 333-644-725 which was calculated using 23² – 14², 2(23)(14), 23² + 14²

It is also the hypotenuse of FIVE other Pythagorean triples.

  • 85-720-725
  • 120-715-725
  • 203-696-725
  • 435-580-725
  • 500-525-725

725 is a palindrome in two bases:

  • 505 BASE 12; note that 5(144) + 0(12) + 5(1) = 725.
  • PP BASE 28 (P = 25 base 10); note that 25(28) + 25(1) = 725.

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725 Factors

718 and a Christmas Star

  • 718 is a composite number.
  • Prime factorization: 718 = 2 x 359
  • The exponents in the prime factorization are 1 and 1. Adding one to each and multiplying we get (1 + 1)(1 + 1) = 2 x 2 = 4. Therefore 718 has exactly 4 factors.
  • Factors of 718: 1, 2, 359, 718
  • Factor pairs: 718 = 1 x 718 or 2 x 359
  • 718 has no square factors that allow its square root to be simplified. √718 ≈ 26.795522.

Today’s puzzle looks like a Christmas Star.

718 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2015-12-21

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Here’s a few facts about the number 718:

178 + 179 + 180 + 181 = 718 making it the sum of 4 consecutive numbers.

718 is the sum of three squares three different ways:

  • 3² + 15² + 22² = 718
  • 9² + 14² + 21² = 718
  • 13² + 15² + 18² = 718

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718 Factors

Could 711 be Eleven 7 in base 64?

  • 711 is a composite number.
  • Prime factorization: 711 = 3 x 3 x 79, which can be written 711 = (3^2) x 79
  • The exponents in the prime factorization are 2 and 1. Adding one to each and multiplying we get (2 + 1)(1 + 1) = 3 x 2  = 6. Therefore 711 has exactly 6 factors.
  • Factors of 711: 1, 3, 9, 79, 237, 711
  • Factor pairs: 711 = 1 x 711, 3 x 237, or 9 x 79
  • Taking the factor pair with the largest square number factor, we get √711 = (√9)(√79) = 3√79 ≈ 26.66458.

Here is today’s puzzle:

711 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-12-14

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Even though in English 711 is a rather fun rhyming number, it has been difficult for me to find interesting facts about it:

7 + 1 + 1 = 9 so 711 is divisible by both 3 and 9.

It can be written as the sum of consecutive numbers three ways:

  • 355 + 356 = 711; that’s two consecutive numbers.
  • 236 + 237 + 238 = 711; that’s three consecutive numbers.
  • 75 + 76 + 77 + 78 + 79 + 80 + 81 + 82 + 83 = 711; that’s nine consecutive numbers.

Is 711 a palindrome in any other base? Not in any base less than 78, but in BASE 78 it is palindrome 99 because 9(78) + 9(1) = 711.

We could ALMOST write that 711 is 11 7 in BASE 64 because 11(64) + 7(1) = 711. However, we can’t REALLY write that because base 10’s eleven would most likely be represented by the letter B in base 64. Thus we would likely write 711 as B7 in Base 64.

Since the words “eleven” and “twelve” do not contain any reference to the word “ten”, I suppose in English we could say that 711 is eleven 7 in base 64. We likely wouldn’t be able to make that same claim in other languages, however.

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711 Factors

705 and Level 2

  • 705 is a composite number.
  • Prime factorization: 705 = 3 x 5 x 47
  • The exponents in the prime factorization are 1, 1, and 1. Adding one to each and multiplying we get (1 + 1)(1 + 1)(1 + 1) = 2 x 2 x 2 = 8. Therefore 705 has exactly 8 factors.
  • Factors of 705: 1, 3, 5, 15, 47, 141, 235, 705
  • Factor pairs: 705 = 1 x 705, 3 x 235, 5 x 141, or 15 x 47
  • 705 has no square factors that allow its square root to be simplified. √705 ≈ 26.551836.

Here is today’s puzzle:

 

705 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2015-12-07

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What else can I tell you about the number 705?

Because 5 is one of its factors, 705 is the hypotenuse of the Pythagorean triple 423-564-705. What is the greatest common factor of those three numbers?

705 is the sum of consecutive numbers several different ways:

  • 352 + 353 = 705; (2 consecutive numbers)
  • 234 + 235 + 236 = 705; (3 consecutive numbers)
  • 139 + 140 + 141 + 142 + 143 = 705; (5 consecutive numbers)
  • 40 + 41 + 42 + 43 + 44 + 45 + 46 + 47 + 48 + 49 + 50 + 51 + 52 + 53 + 54 = 705; (15 consecutive numbers)

705 is palindrome 1A1 in base 22; note that A is equivalent to 10 base 10, 22² = 484, and 1(484) + 10(22) + 1(1) = 705.

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705 Factors