1226 Happy Birthday to My Sister, Sue

I don’t make puzzles bigger than 12 × 12 very often, but I decided to make this one, a 17 × 17 Mystery Level for my sister’s birthday. I know she can solve smaller ones without any problems, so I wanted to give her a challenge. Happy birthday, Sue. I hope you have a great day and enjoy solving this one.

Note that with a bigger table there are several more possible common factors:

Is 4, 8, or 16 the common factor needed for 64 and 32 or for 16 and 48?
Is 7 or 14 the common factor needed for 14 and 70?
Is 6, 10, or 15 the common factor needed for 60 and 90?

As always there is only one solution. The table below will help anyone not familiar with some of the lesser known multiplication facts needed to solve the puzzle.

Now I’ll share some information about the number 1226:

  • 1226 is a composite number.
  • Prime factorization: 1226 = 2 × 613
  • The exponents in the prime factorization are 1 and 1. Adding one to each and multiplying we get (1 + 1)(1 + 1) = 2 × 2 = 4. Therefore 1226 has exactly 4 factors.
  • Factors of 1226: 1, 2, 613, 1226
  • Factor pairs: 1226 = 1 × 1226 or 2 × 613
  • 1226 has no square factors that allow its square root to be simplified. √1226 ≈ 35.01428

35² + 1² = 1226

1226 is the hypotenuse of a Pythagorean triple:
70-1224-1226 calculated from 2(35)(1), 35² – 1², 35² + 1²

Advertisements

1221 and Level 1

This puzzle is like a multiplication table with its factors in a different order. Can you figure out where the factors from 1 to 10 go in both the first column and the top row? Afterward, can you correctly fill in every cell of this mixed-up multiplication table?

Let me share some facts about the number 1221:

  • 1221 is a composite number.
  • Prime factorization: 1221 = 3 × 11 × 37
  • 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 × 2 × 2 = 8. Therefore 1221 has exactly 8 factors.
  • Factors of 1221: 1, 3, 11, 33, 37, 111, 407, 1221
  • Factor pairs: 1221 = 1 × 1221, 3 × 407, 11 × 111, or 33 × 37
  • 1221 has no square factors that allow its square root to be simplified. √1221 ≈ 34.94281

1 × 11 × 111 = 1221

1221 is the sum of five consecutive prime numbers:
233 + 239 + 241 + 251 + 257 = 1221

1221 is the hypotenuse of a Pythagorean triple:
396-1155-1221 which is 33 times (12-35-37)

Not only is 1221 a palindrome in base 10 but look at it in these other bases:
It’s 14341 in BASE 5,
5353 in BASE 6,
272 in BASE 23, and
it’s XX in BASE 36 because 33(36) + 33(1) = 33(37) = 1221

1220 Challenge Puzzle

The last challenge puzzle was particularly difficult. This one won’t be nearly as bad. Try it and see if you can figure it out!

Print the puzzles or type the solution in this excel file: 12 factors 1211-1220

Here are a few facts about the number 1220:

  • 1220 is a composite number.
  • Prime factorization: 1220 = 2 × 2 × 5 × 61, which can be written 1220 = 2² × 5 × 61
  • 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 × 2 × 2 = 12. Therefore 1220 has exactly 12 factors.
  • Factors of 1220: 1, 2, 4, 5, 10, 20, 61, 122, 244, 305, 610, 1220
  • Factor pairs: 1220 = 1 × 1220, 2 × 610, 4 × 305, 5 × 244, 10 × 122, or 20 × 61
  • Taking the factor pair with the largest square number factor, we get √1220 = (√4)(√305) = 2√305 ≈ 34.9285

1220 is the sum of consecutive prime numbers: 607 + 613 = 1220

1220 is the sum of two squares two different ways:
32² + 14² = 1220
34² + 8² = 1220

1220 is the hypotenuse of four Pythagorean triples:
220-1200-1220 which is 20 times (11-60-61)
544-1092-1220 calculated from 2(34)( 8), 34² – 8², 34² + 8²
and is also 4 times (136-273-305)
828-896-1220 calculated from 32² – 14², 2(32)(14), 32² + 14²
and is also 4 times (207-224-305)
732-976-1220 which is (3-4-5) times 244

1219 is a Centered Triangular Number

If you look at an ordered list of centered triangular numbers, 1219 will be the 29th number on the list.

Study this graphic to see why:

Here’s more about the number 1219:

  • 1219 is a composite number.
  • Prime factorization: 1219 = 23 × 53
  • The exponents in the prime factorization are 1 and 1. Adding one to each and multiplying we get (1 + 1)(1 + 1) = 2 × 2 = 4. Therefore 1219 has exactly 4 factors.
  • Factors of 1219: 1, 23, 53, 1219
  • Factor pairs: 1219 = 1 × 1219 or 23 × 53
  • 1219 has no square factors that allow its square root to be simplified. √1219 ≈ 34.91418

1219 is the sum of the thirteen prime numbers from 67 to 127.

1219 is also the hypotenuse of a Pythagorean triple:
644-1035-1219 which is 23 times (28-45-53)

 

1218 Mystery Level

Working on this Mystery level puzzle may seem easy at first, but will it remain easy until its unique solution is found? Only those who solve it will know the answer to that question!

Print the puzzles or type the solution in this excel file: 12 factors 1211-1220

Here are some facts about the number 1218:

  • 1218 is a composite number.
  • Prime factorization: 1218 = 2 × 3 × 7 × 29
  • The exponents in the prime factorization are 1, 1, 1, and 1. Adding one to each and multiplying we get (1 + 1)(1 + 1)(1 + 1)(1 + 1) = 2 × 2 × 2 × 2 = 16. Therefore 1218 has exactly 16 factors.
  • Factors of 1218: 1, 2, 3, 6, 7, 14, 21, 29, 42, 58, 87, 174, 203, 406, 609,
  • 1218
  • Factor pairs: 1218 = 1 × 1218, 2 × 609, 3 × 406, 6 × 203, 7 × 174, 14 × 87, 21 × 58, or 29 × 42
  • 1218 has no square factors that allow its square root to be simplified. √1218 ≈ 34.89986

1218 is the hypotenuse of a Pythagorean triple:
840-882-1218 which is (20-21-29) times 42

 

1216 and Level 6

Is 6 or 9 the needed common factor for 54 and 36?
The other one will be the common factor for 72 and 18.

Will 5 or 10 be the common factor of 30 and 50?
Will 2 or 4 be the common factor of 16 and 4?

Don’t guess the answers to those questions! The other clues in the puzzle will help you find the answers. Will you be stumped or will you triumph?

Print the puzzles or type the solution in this excel file: 12 factors 1211-1220

Now I’ll share some information about the number 1216:

  • 1216 is a composite number.
  • Prime factorization: 1216 = 2 × 2 × 2 × 2 × 2 × 2 × 19, which can be written 1216 = 2⁶ × 19
  • The exponents in the prime factorization are 6, and 1. Adding one to each and multiplying we get (6 + 1)(1 + 1) = 7 × 2 = 14. Therefore 1216 has exactly 14 factors.
  • Factors of 1216: 1, 2, 4, 8, 16, 19, 32, 38, 64, 76, 152, 304, 608, 1216
  • Factor pairs: 1216 = 1 × 1216, 2 × 608, 4 × 304, 8 × 152, 16 × 76, 19 × 64, or 32 × 38
  • Taking the factor pair with the largest square number factor, we get √1216 = (√64)(√19) = 8√19 ≈ 34.87119

1216 is the sum of the ten prime numbers between 100 and 150:
101 + 103 + 107 + 109 + 113 + 127 + 131 + 137 + 139 + 149 = 1216

1216 is the 19th nonagonal number because
19(7·19 – 5)/2 = 1216, in other words because 19 × 64 = 1216

1215 and Level 5

Level 5 puzzles are a little trickier than level 4 puzzles, but you can still use logic to find the unique solution to today’s puzzle. Stick with it!

Print the puzzles or type the solution in this excel file: 12 factors 1211-1220

Here is some information about the number 1215:

  • 1215 is a composite number.
  • Prime factorization: 1215 = 3 × 3 × 3 × 3 × 3 × 5, which can be written 1215 = 3⁵ × 5
  • The exponents in the prime factorization are 5 and 1. Adding one to each and multiplying we get (5 + 1)(1 + 1) = 6 × 2 = 12. Therefore 1215 has exactly 12 factors.
  • Factors of 1215: 1, 3, 5, 9, 15, 27, 45, 81, 135, 243, 405, 1215
  • Factor pairs: 1215 = 1 × 1215, 3 × 405, 5 × 243, 9 × 135, 15 × 81, or 27 × 45
  • Taking the factor pair with the largest square number factor, we get √1215 = (√81)(√15) = 9√15 ≈ 34.85685

1215 is the hypotenuse of a Pythagorean triple:
729-972-1215 which is (3-4-5) times 243

 

1214 and Level 4

Even though I don’t tell you the order to consider the clues in today’s puzzle, you can still solve it. Just use logic and your knowledge of a standard 12 × 12 multiplication table to find its unique solution. Good luck!

Print the puzzles or type the solution in this excel file: 12 factors 1211-1220

Now I’ll share a few facts about the number 1214:

  • 1214 is a composite number.
  • Prime factorization: 1214 = 2 × 607
  • The exponents in the prime factorization are 1 and 1. Adding one to each and multiplying we get (1 + 1)(1 + 1) = 2 × 2 = 4. Therefore 1214 has exactly 4 factors.
  • Factors of 1214: 1, 2, 607, 1214
  • Factor pairs: 1214 = 1 × 1214 or 2 × 607
  • 1214 has no square factors that allow its square root to be simplified. √1214 ≈ 34.8425

1214 is the sum of six consecutive prime numbers:
191 + 193 + 197 + 199 + 211 + 223 = 1214

1212 and Level 2

I know you will find at least some of today’s puzzle to be easy, and maybe even all of it. Why not give it a try? You might just have fun solving it, too!

Print the puzzles or type the solution in this excel file: 12 factors 1211-1220

When we learn about the number 1212 we get to think about twelve a lot. 1212 has twelve factors and, of course, one of them is 12.

  • 1212 is a composite number.
  • Prime factorization: 1212 = 2 × 2 × 3 × 101, which can be written 1212 = 2² × 3 × 101
  • 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 × 2 × 2 = 12. Therefore 1212 has exactly 12 factors.
  • Factors of 1212: 1, 2, 3, 4, 6, 12, 101, 202, 303, 404, 606, 1212
  • Factor pairs: 1212 = 1 × 1212, 2 × 606, 3 × 404, 4 × 303, 6 × 202, or 12 × 101
  • Taking the factor pair with the largest square number factor, we get √1212 = (√4)(√303) = 2√303 ≈ 34.81379

1212 is the sum of the fourteen prime numbers from 59 to 113.
It is also the sum of the twelve prime numbers from 73 to 131.
Do you know what all those prime numbers are?

1212 is the hypotenuse of a Pythagorean triple:
240-1188-1212 which is 12 times (20-99-101)

1211 and Level 1

Today we are reminded that the world can be a very complicated place. Today’s puzzle isn’t the least bit complicated. Just write the numbers from 1 to 12 in the first column and the top row so that the puzzle looks like a multiplication table (but with the factors not in their usual places.) Afterward, you can fill in the rest of the table. You can do this!

Print the puzzles or type the solution in this excel file: 12 factors 1211-1220

Now I’d like to share some information about the number 1211:

  • 1211 is a composite number.
  • Prime factorization: 1211 = 7 × 173
  • The exponents in the prime factorization are 1 and 1. Adding one to each and multiplying we get (1 + 1)(1 + 1) = 2 × 2 = 4. Therefore 1211 has exactly 4 factors.
  • Factors of 1211: 1, 7, 173, 1211
  • Factor pairs: 1211 = 1 × 1211 or 7 × 173
  • 1211 has no square factors that allow its square root to be simplified. √1211 ≈ 34.79943

1211 is the sum of the seventeen prime numbers from 37 to 107.
It is also the sum of seven consecutive primes:
157 + 163 + 167 + 173 + 179 + 181 + 191 = 1211

1211 is the hypotenuse of a Pythagorean triple:
364-1155-1211 which is 7 times (52-165-173)