503 and Level 2

503 = (2^3) + (3^3) + (5^3) + (7^3) which is the sum of the cubes of the first four prime numbers. 503 is the smallest prime number that is the sum of consecutive cubes of prime numbers.

503 is also the sum of three consecutive prime numbers: 163, 167, and 173.

503 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2015-05-25

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  • 503 is a prime number.
  • Prime factorization: 503 is prime.
  • The exponent of prime number 503 is 1. Adding 1 to that exponent we get (1 + 1) = 2. Therefore 503 has exactly 2 factors.
  • Factors of 503: 1, 503
  • Factor pairs: 503 = 1 x 503
  • 503 has no square factors that allow its square root to be simplified. √503 ≈ 22.42766

How do we know that 503 is a prime number? If 503 were not a prime number, then it would be divisible by at least one prime number less than or equal to √503 ≈ 22.4. Since 503 cannot be divided evenly by 2, 3, 5, 7, 11, 13, 17, or 19, we know that 503 is a prime number.

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503 Factors

502 and Level 1

The prime factorization of 502 is 2 x 251. How many integers less than or equal to 502 do not have either of those numbers in their prime factorizations?

There is actually a function that counts how many. It is called the totient function or Euler’s totient function and looks like φ(502).

502 is the first integer that has both 2 and 251 in its prime factorization so finding φ(502) will be easy: first eliminate the 251 integers less than or equal to 502 that are divisible by 2. Then eliminate 251 because it is the only remaining number that is divisible by 502’s other prime factor. Thus φ(502) = 502 – 251 – 1 = 250.

Notice that 502 and 250 use the same digits. I learned this fact about the number 502 and φ(502) by reading OEIS.org.

502 Puzzle

Print the puzzles or type the solution on this excel file: 10 Factors 2015-05-25

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  • 502 is a composite number.
  • Prime factorization: 502 = 2 x 251
  • 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 502 has exactly 4 factors.
  • Factors of 502: 1, 2, 251, 502
  • Factor pairs: 502 = 1 x 502 or 2 x 251
  • 502 has no square factors that allow its square root to be simplified. √502 ≈ 22.4053565

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502 Factors

501 and Level 6

2 + 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 + 61 = 501. That was the first 18 prime numbers.

501 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-05-18

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  • 501 is a composite number.
  • Prime factorization: 501 = 3 x 167
  • 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 501 has exactly 4 factors.
  • Factors of 501: 1, 3, 167, 501
  • Factor pairs: 501 = 1 x 501 or 3 x 167
  • 501 has no square factors that allow its square root to be simplified. √501 ≈ 22.383029

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501 Logic

500 Pick Your Pony! Who’ll Win This Number of Factors Horse Race?

Today I factor the number 500. How many factors does it have? Each number between 401 and 500 has at least 2 factors, but no more than 24 factors.

What if we had a horse race between the number of factors? Click on the graphic below to see a gif of the numbers racing against each other. Before you click, pick your pony. Will 2, 4, 6, 8, 9, 10, 12, 14, 16, 18, 20, or 24 be the number of factors of more integers between 401 and 500 than any other number? Click on the graphic to find out!

500 Horse Race

Did you see the lead change a couple of times? How did your pony do? Which pony will you choose in the 501 to 600 race?

Remarkably, only 37 of these one hundred numbers have reducible square roots. That’s only 37%, which is significantly lower than in the 40% or 39% of previous hundreds as this graphic illustrates:

500 Reducible vs. Non-Reducible

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  • 500 is a composite number.
  • Prime factorization: 500 = 2 x 2 x 5 x 5 x 5, which can be written 500 = (2^2) x (5^3)
  • The exponents in the prime factorization are 2 and 3. Adding one to each and multiplying we get (2 + 1)(3 + 1) = 3 x 4 = 12. Therefore 500 has exactly 12 factors.
  • Factors of 500: 1, 2, 4, 5, 10, 20, 25, 50, 100, 125, 250, 500
  • Factor pairs: 500 = 1 x 500, 2 x 250, 4 x 125, 5 x 100, 10 x 50, or 20 x 25
  • Taking the factor pair with the largest square number factor, we get √500 = (√100)(√5) = 10√5 ≈ 22.36067977

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If you didn’t want to click, you can still see the horse race below, but the numbers from 401 to 500 will be much clearer if you click.

Factors of Numbers from 401 to 500 Horse Race

make animated gifs like this at MakeAGif

499 and Level 5

499 is the sum of a nice bunch of consecutive prime numbers:

  • 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 + 61 = 499. That’s 17 consecutive primes.

499 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-05-18

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  • 499 is a prime number.
  • Prime factorization: 499 is prime.
  • The exponent of prime number 499 is 1. Adding 1 to that exponent we get (1 + 1) = 2. Therefore 499 has exactly 2 factors.
  • Factors of 499: 1, 499
  • Factor pairs: 499 = 1 x 499
  • 499 has no square factors that allow its square root to be simplified. √499 ≈ 22.3383079

How do we know that 499 is a prime number? If 499 were not a prime number, then it would be divisible by at least one prime number less than or equal to √499 ≈ 22.3383. Since 499 cannot be divided evenly by 2, 3, 5, 7, 11, 13, 17, or 19, we know that 499 is a prime number.

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499 Logic

498 and Level 4

As I searched for something interesting yet understandable to say about the number 498, I learned that 498 is the third 167-gonal number when I looked at virtuescience.com/polygonal-numbers. I also found out that “Charlie Eppes” has a blog called Numbers that features graphic representations of the number 498 and a lot of other numbers, too.

You may find puzzle #498 to be a little trickier than most Level 4 puzzles, but I know you can still meet the challenge.

498 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-05-18

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  • 498 is a composite number.
  • Prime factorization: 498 = 2 x 3 x 83
  • 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 498 has exactly 8 factors.
  • Factors of 498: 1, 2, 3, 6, 83, 166, 249, 498
  • Factor pairs: 498 = 1 x 498, 2 x 249, 3 x 166, or 6 x 83
  • 498 has no square factors that allow its square root to be simplified. √498 ≈ 22.3159136

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498 Logic

497 and Level 3

497 is the sum of a five consecutive prime numbers: 89 + 97 + 101 + 103 + 107 = 497.

497 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-05-18

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  • 497 is a composite number.
  • Prime factorization: 497 = 7 x 71
  • 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 497 has exactly 4 factors.
  • Factors of 497: 1, 7, 71, 497
  • Factor pairs: 497 = 1 x 497 or 7 x 71
  • 497 has no square factors that allow its square root to be simplified. √497 ≈ 22.2934968

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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.

497 Factors

Perfect Number 496 and Level 2

  • 6 is the first perfect number because 1 + 2 + 3 = 6. Also notice that (2^1)(2^2 – 1) = 2 x 3 = 6.
  • 28 is the second perfect number because 1 + 2 + 4 + 7 + 14 = 28. Hmm… (2^2)(2^3 – 1) = 4 x 7 = 28.
  • (2^3)(2^4 – 1) = 8 x 15 = 120 is NOT a perfect number because 1 + 2 + 3 + 4 + 5 + 6 + 8 + 10 + 12 + 15 + 20 + 24 + 30 + 40 + 60 = 240 which is two times what it needs to be.
  • 496 is (2^4)(2^5 – 1) = 16 x 31. So why is 496 the third perfect number? Everything you need to know to figure out the answer to that question can be found somewhere in this post.
  • 2016 is (2^5)(2^6 – 1) = 32 x 63, and 2016 is also NOT a perfect number.

6, 28, and 496 are all triangular numbers as well as hexagonal numbers, but 120 and 2016 can also make that claim.

The clues in yesterday’s Find the Factors puzzle were all perfect squares. Today’s puzzle is only a little more difficult. You can solve it, too!

496 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-05-18

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  • 496 is a composite number.
  • Prime factorization: 496 = 2 x 2 x 2 x 2 x 31, which can be written 496 = (2^4) x 31
  • The exponents in the prime factorization are 4 and 1. Adding one to each and multiplying we get (4 + 1)(1 + 1) = 5 x 2 = 10. Therefore 496 has exactly 10 factors.
  • Factors of 496: 1, 2, 4, 8, 16, 31, 62, 124, 248, 496
  • Factor pairs: 496 = 1 x 496, 2 x 248, 4 x 124, 8 x 62, or 16 x 31
  • Taking the factor pair with the largest square number factor, we get √496 = (√16)(√31) = 4√31 ≈ 22.271057

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496 Factors

495 and Level 1

495 has an almost magical property and is known as the Kaprekar constant for 3 digit numbers. What does that mean?

Take any 3 digit number that has at least 2 different digits. Write the digits from greatest to least to create a new 3-digit number. From that number subtract the same digits written in reverse order. Repeat this process, and you will get the number 495 in no more than seven iterations. This graphic shows this process applied to the number 101.

495-Kaprekar Transformation

The following puzzle can easily transform into a multiplication table if you first find all the square factors of the given clues. Go ahead give it a try!

495 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-05-18

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  • 495 is a composite number.
  • Prime factorization: 495 = 3 x 3 x 5 x 11, which can be written 495 = (3^2) x 5 x 11
  • 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 495 has exactly 12 factors.
  • Factors of 495: 1, 3, 5, 9, 11, 15, 33, 45, 55, 99, 165, 495
  • Factor pairs: 495 = 1 x 495, 3 x 165, 5 x 99, 9 x 55, 11 x 45, or 15 x 33
  • Taking the factor pair with the largest square number factor, we get √495 = (√9)(√55) = 3√55 ≈ 22.248595

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495 Factors

494 My First Microfilm Treasure Hunt

494 is the hypotenuse of one Pythagorean triple: 190-456-494. What is the greatest common factor of those three numbers?

  • 494 is a composite number.
  • Prime factorization: 494 = 2 x 13 x 19
  • 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 494 has exactly 8 factors.
  • Factors of 494: 1, 2, 13, 19, 26, 38, 247, 494
  • Factor pairs: 494 = 1 x 494, 2 x 247, 13 x 38, or 19 x 26
  • 494 has no square factors that allow its square root to be simplified. √494 ≈ 22.22611

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Years ago my husband and I wanted to research his family tree so I decided to visit the Family History library in downtown Salt Lake City on 8 April 2010. At that time we knew the names of his four grandparents, his eight great-grandparents, and one great-great-grandfather. We knew all of these people were born in Hungary. The information we had was that two of his grandparents were born in a little town called Gyoma in what is now eastern Hungary. We had no idea where his other two grandparents were born. This day was the first time I ever looked at any Hungarian genealogical records. I knew maybe ten words in Hungarian, and I had never even seen similar records in English.

The records were recorded on microfilm which were sorted into Roman Catholic, Reformed Hungarian, Lutheran, and Jewish records. I had no idea what religion his ancestors were, but based on the number of microfilms available for each religion in Gyoma, chances were that they belonged to the Reformed Church. I found a microfilm with Kereszteltek (christening) records from 1883-1895. A volunteer showed me how to put the microfilm on a the reader, and I started looking. I made notes of which records interested me. It was so exciting to find records that had names of people I had heard stories about. It was my intention to photocopy as many family records as I could, scan them into my home computer, and email them to my son, David, who speaks Hungarian fluently but lived in Qatar at the time. However, when I went to make copies, I was pleasantly surprised to learn that I could actually copy the records directly onto a flash drive!

I emailed my son that the five hours I spent at the family history library were well spent. I didn’t find any of the christening records I was expecting to find but found about thirteen records of his ancestor’s siblings. I attached the records to the email and waited for morning to arrive in Qatar so he could reply.

The next day he emailed me back, “I only had time to look at the first four (records). I’ll check the rest later. I’ve written some notes below, but I should let you know that you basically just found four people who aren’t related to us.” He then wrote in English what each of the records said.

Later he emailed me, “To continue the bad news, Now that I look at all of them, I can see that they (the great-grandparents) are all listed as godparents. This should explain why you didn’t find much of what you were actually looking for. Now you know, and should be able to look for names in the right column.”

He sent me translations of the page headings so I wouldn’t go wrong in the future. The christening records were two pages wide. Here are the headings with his translations for the first page:

And here are the headings with translations for the 2nd page.

So there you have it. Since I knew so little Hungarian and so little about how christening records are organized, I thought the godparents were the parents.

I had to wait a whole week before I could go back to the library, but this first visit was not a total bust. We still learned a few things about my husband’s great-grandfather, Dániel Finta, that we didn’t know before. We learned that he worked in a factory making shoes because his profession was given next to his name on at least one record. We learned that Dániel was asked on several occasions to be a godfather. Sometimes his wife was the godmother with him, and sometimes his mother was. Because I found these records we now knew his mother’s name, Sára Bíró, as well. We also learned that Dániel belonged to the Reformed Church and his wife, Emília Pribelszky, was Lutheran.

I was grateful for what we had learned and anxious to return again.

How successful were you the first time you looked into your family history? If you were discouraged, please give it another try. It is so worth it. If you were successful, you know exactly what I mean.