535 and Level 6

535 is the hypotenuse of the Pythagorean triple 321-428-535. Can you find the greatest common factor of those three numbers?

535 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2015-06-22

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  • 535 is a composite number.
  • Prime factorization: 535 = 5 x 107
  • 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 535 has exactly 4 factors.
  • Factors of 535: 1, 5, 107, 535
  • Factor pairs: 535 = 1 x 535 or 5 x 107
  • 535 has no square factors that allow its square root to be simplified. √535 ≈ 23.130067

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535 Logic

534 and Level 5

534 is made of three consecutive digits so it can be evenly divided by three.

534 is the sum of consecutive primes: 127 + 131 + 137 + 139 = 534.

534 is the hypotenuse of the Pythagorean triple 234-480-534. Can you find the greatest common factor of those three numbers?

534 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2015-06-22

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  • 534 is a composite number.
  • Prime factorization: 534 = 2 x 3 x 89
  • 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 534 has exactly 8 factors.
  • Factors of 534: 1, 2, 3, 6, 89, 178, 267, 534
  • Factor pairs: 534 = 1 x 534, 2 x 267, 3 x 178, or 6 x 89
  • 534 has no square factors that allow its square root to be simplified. √534 ≈ 23.108440.

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534 Logic

533 and Level 4

533 is the sum of consecutive primes two different ways: 173 + 179 + 181 = 533 = 101 + 103 + 107 + 109 + 113.

533 = (23^2) + (2^2), and 533 = (22^2) + (7^2)

533 is the hypotenuse of four Pythagorean triples. Some of the triples have a greatest common factor greater than one, and the rest are primitive. Which are which?

  • 92-525-533
  • 117-520-533
  • 205-492-533
  • 308-435-533

533 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2015-06-22

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  • 533 is a composite number.
  • Prime factorization: 533 = 13 x 41
  • 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 533 has exactly 4 factors.
  • Factors of 533: 1, 13, 41, 533
  • Factor pairs: 533 = 1 x 533 or 13 x 41
  • 533 has no square factors that allow its square root to be simplified. √533 ≈ 23.08679

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533 Logic

532 and Level 3

532 is the sum of consecutive prime numbers 263 and 269.

532 is also the 19th pentagonal number.

532 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2015-06-22

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  • 532 is a composite number.
  • Prime factorization: 532 = 2 x 2 x 7 x 19, which can be written 532 = (2^2) x 7 x 19
  • The exponents in the prime factorization are 1, 2, and 1. Adding one to each and multiplying we get (2 + 1)(1 + 1)(1 + 1) = 3 x 2 x 2 = 12. Therefore 532 has exactly 12 factors.
  • Factors of 532: 1, 2, 4, 7, 14, 19, 28, 38, 76, 133, 266, 532
  • Factor pairs: 532 = 1 x 532, 2 x 266, 4 x 133, 7 x 76, 14 x 38, or 19 x 28
  • Taking the factor pair with the largest square number factor, we get √532 = (√4)(√133) = 2√133 ≈ 23.065125

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A Logical Approach to solve a FIND THE FACTORS puzzle: Find the column or row with two clues and find their common factor. Write the corresponding factors in the factor column (1st column) and factor row (top row).  Because this is a level three puzzle, you have now written a factor at the top of the factor column. Continue to work from the top of the factor column to the bottom, finding factors and filling in the factor column and the factor row one cell at a time as you go.

532 Factors

 

531 and Level 2

5 + 3 + 1 = 9 so 531 is divisible by 3 and by 9. Because it can be evenly divided by 9, it’s square root can be reduced.

531 ÷ 9 = 59, a prime number which obviously has no square factors. Thus √531 = (√9)(√59) = 3√59 in its most reduced form.

531 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2015-06-22

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  • 531 is a composite number.
  • Prime factorization: 531 = 3 x 3 x 59, which can be written 531 = (3^2) x 59
  • 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 531 has exactly 6 factors.
  • Factors of 531: 1, 3, 9, 59, 177, 531
  • Factor pairs: 531 = 1 x 531, 3 x 177, or 9 x 59
  • Taking the factor pair with the largest square number factor, we get √531 = (√9)(√59) = 3√59 ≈ 23.04343724

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531 Factors

 

530 and Level 1

The first three perfect numbers are 6, 28, and 496. Their sum is 530.

Can you find the greatest common factors for each of these Pythagorean triples?

  • 46-528-530
  • 192-494-530
  • 280-450-530
  • 318-424-530

530 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2015-06-22

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  • 530 is a composite number.
  • Prime factorization: 530 = 2 x 5 x 53
  • 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 530 has exactly 8 factors.
  • Factors of 530: 1, 2, 5, 10, 53, 106, 265, 530
  • Factor pairs: 530 = 1 x 530, 2 x 265, 5 x 106, or 10 x 53
  • 530 has no square factors that allow its square root to be simplified. √530 ≈ 23.02172886644

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530 Factors

528 and Level 6

528 feet is one tenth of a mile. Joseph Nebus has written a fascinating post on WHY a mile is 5280 feet. Factoring that number is part of the reason.

Since 528 = (32 x 33)/ 2, we know that 528 is the 32nd triangular number.

Thus, 1 + 2 + 3 + 4 + . . . . . + 29 + 30 + 31 + 32 = 528.

528 can be written as the difference of two squares six different ways:

528 Difference of Two Squares

How did I find them? Choose a factor pair where both factors are even or both factors are odd. Average the two factors and that will be the first number to be squared. Square it and subtract 528. Take the square root of the result. That number is the second number in the difference of two squares.

528 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-06-15

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  • 528 is a composite number.
  • Prime factorization: 528 = 2 x 2 x 2 x 2 x 3 x 11, which can be written 528 = (2^4) x 3 x 11
  • The exponents in the prime factorization are 4, 1 and 1. Adding one to each and multiplying we get (4 + 1)(1 + 1)(1 + 1) = 5 x 2 x 2 = 20. Therefore 528 has exactly 20 factors.
  • Factors of 528: 1, 2, 3, 4, 6, 8, 11, 12, 16, 22, 24, 33, 44, 48, 66, 88, 132, 176, 264, 528
  • Factor pairs: 528 = 1 x 528, 2 x 264, 3 x 176, 4 x 132, 6 x 88, 8 x 66, 11 x 48, 12 x 44, 16 x 33 or 22 x 24
  • Taking the factor pair with the largest square number factor, we get √528 = (√16)(√33) = 4√33 ≈ 22.97825

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528 Logic

 

527 and Level 5

527 is the sum of consecutive primes including all the prime numbers in its prime factorization. Can you list those consecutive primes?

527 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-06-15

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  • 527 is a composite number.
  • Prime factorization: 527 = 17 x 31
  • 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 527 has exactly 4 factors.
  • Factors of 527: 1, 17, 31, 527
  • Factor pairs: 527 = 1 x 527 or 17 x 31
  • 527 has no square factors that allow its square root to be simplified. √527 ≈ 22.95648

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527 Logic

 

526 is a Centered Pentagonal Number

I am excited that Kerrydunton included the Find the Factors puzzles on a list of great maths starters.

1 + 5 + 10 + 15 + 20 + 25 + 30 + 35 + 40 + 45 + 50 + 55 + 60 + 65 + 70 = 526. Thus, 526 is the 15th centered pentagonal number.

The above equation is the same as saying that 526 is one more than five times the 14th triangular number.

526 Centered Pentagonal Number

The last digit of a centered pentagonal number is always 1 or 6. Triangular numbers greater than 3 are always composite numbers, but centered pentagonal numbers ending in 1 might be prime numbers. For example 31, 181, 331, 601, 1051, 1381, and 3331 are centered pentagonal numbers and prime numbers.

526 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-06-15

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  • 526 is a composite number.
  • Prime factorization: 526 = 2 x 263
  • 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 526 has exactly 4 factors.
  • Factors of 526: 1, 2, 263, 526
  • Factor pairs: 526 = 1 x 526 or 2 x 263
  • 526 has no square factors that allow its square root to be simplified. √526 ≈ 22.93468988

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526 Logic

525 and Level 3

525 = (23 + 2)(23 – 2) = (23^2) – (2^2) makes 525 the longer leg in what primitive Pythagorean triple?

Why do people enjoy number puzzles? A mathemagician friend once stated that a key reason was loving to solve mysteries.

I find making and solving puzzles to be quite relaxing. Solve the mystery or relax a little finding the factors of this puzzle:

525 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-06-15

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  • 525 is a composite number.
  • Prime factorization: 525 = 3 x 5 x 5 x 7, which can be written 525 = 2 x (5^2) x 7
  • The exponents in the prime factorization are 1, 2, and 1. Adding one to each and multiplying we get (1 + 1)(2 + 1)(1 + 1) = 2 x 3 x 2 = 12. Therefore 525 has exactly 12 factors.
  • Factors of 525: 1, 3, 5, 7, 15, 21, 25, 35, 75, 105, 175, 525
  • Factor pairs: 525 = 1 x 525, 3 x 175, 5 x 105, 7 x 75, 15 x 35, or 21 x 25
  • Taking the factor pair with the largest square number factor, we get √525 = (√25)(√21) = 5√21 ≈ 22.912878

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A Logical Approach to solve a FIND THE FACTORS puzzle: Find the column or row with two clues and find their common factor. Write the corresponding factors in the factor column (1st column) and factor row (top row).  Because this is a level three puzzle, you have now written a factor at the top of the factor column. Continue to work from the top of the factor column to the bottom, finding factors and filling in the factor column and the factor row one cell at a time as you go.

525 Factors