Perfect Practice Makes Perfect

# Number Sense

## Holiday Puzzle 2015 #10 – Snowflake Puzzles

December 10th, 2015 by John Lehet

“Begin doing what you want to do now. We are not living in eternity. We have only this moment, sparkling like a star in our hand and melting like a snowflake.” – Francis Bacon

Today’s puzzle is called a Snowflake Puzzle.  This is an extension of the Kuruko Puzzles that I created. Like Kurulko puzzles, they are similar to Sudoku puzzles.  I call them Snowflake puzzles because of their shape.  Snowflakes are symmetric shapes with six points.   The Snowflake puzzle follows this design.  It is comprised of 42 hexagons (six sided shapes).  There are white and yellow hexagons.  To complete the puzzle you must fill in each of the empty white hexagons.  There are two simple rules to follow:

1. Surrounding each yellow hexagon there are six white hexagons, these must contain the numbers 1 through 6 (each number once and only once)

2. The number in each yellow hexagon is the sum of the numbers in the three white hexagons that point to it (with a black triangle).

Here’s a snowflake puzzle for you to try –   Click here for a pdf file.

If you like the snowflake puzzle, take a look at the book of 100 Kuruko Puzzles that I wrote which is available on Amazon.com.  Good Luck and pass the puzzles onto others who may enjoy them!

## Holiday Puzzle 2015 #7 – Hex Codes

December 7th, 2015 by John Lehet

“” –

Today’s puzzles are Hex Codes.  Each puzzle is a collection of adjacent hexagons that follow a pattern.  Each hexagon contains either a number/letter or is empty.  The objective is for you to fill in empty hexagons with the correct number/letter that follows the given pattern.  You must determine the pattern that each puzzle exhibits in order to correctly complete each puzzles.  The hexagons may vary in color which may be of importance (hint, hint, nudge, nudge).  Some of the puzzles may use addition or subtraction, while others may utilize some other connection (like adjacent hexagons or the color) between certain attributes.  That’s all for you to figure out.  These puzzles can be very challenging.

All you need to do is to figure out the pattern in each puzzle and then use it fill in empty hexagons.  Below are four puzzles to try.  If you like them, click here for a pdf file with more.  Best of luck!

As always, I hope you enjoyed these puzzles.  Please pass them onto others who may enjoy them!

## Holiday Puzzle 2015 #5 – Alphametics

December 5th, 2015 by John Lehet

Believe you can and you’re halfway there.” – Theodore Roosevelt

Today’s puzzle is a great puzzle that everyone can enjoy. They are called alphametics. In each puzzle, there is a simple addition problem. However, instead of using numbers, letters are used. Each letter stands for a single digit number (e.g. 0,1,2,3,4,5,6,7,8 or 9). Within each puzzle, a number can be associated with only one letter, so two different letters can not equal the same number. The meaning of the letters may change from puzzle to puzzle, so “N” may be “5” in the first puzzle and may be “3” in the second puzzle. The objective is to assign each letter a number so the statement is correct – in other words, it all adds up. It sounds straight-forward and is easy to understand, but may be very challenging. Here’s an example:

In this example, there are eight different letters each matched with a unique number, so F=1, O=3, U=6, R=7 and so on. Make sure you understand the example. When you do, try the following puzzles. I have created three interactive puzzles below.

puzzle 1

The first puzzle has eight unique letters (L,E,T,I,S,N,O,W) with only T duplicated. Use any of the numbers 0 through 9 (two numbers will not be used) to solve. There are numerous solutions. Enter your answer in the boxes and select Check when complete to check your answers.

puzzle 2

The second puzzle has eight unique letters (F,O,U,R,N,E,I,V) with F,O,E duplicated. Use any of the numbers 0 through 9 (two numbers will not be used) to solve. There are numerous solutions. An extra challenge is to try to solve this puzzle using only the numbers 0 through 7 (try not to use 8 and 9). Enter your answer in the boxes and select Check when complete to check your answers.

puzzle 3

I’ve heard it said that two wrongs don’t make a right, but three lefts do! The third puzzle has eight unique letters (L,E,F,T,R,I,G,H) with L,E,F,T duplicated. Use any of the numbers 0 through 9 (two numbers will not be used) to solve. There are numerous solutions. An extra challenge is to try to solve this puzzle using only the numbers 1 through 8 (try not to use 0 and 9). Enter your answer in the boxes and select Check when complete to check your answers.

I hope you enjoy these puzzles. Good Luck and pass the puzzles onto others who may enjoy them!

## Holiday Puzzle 2015 #4 – Number Sense Puzzles

December 4th, 2015 by John Lehet

Excellence is the gradual result of always striving to do better.” – Pat Riley

Today’s puzzle is a Number Sense Puzzle.  They are geared for younger puzzlers to help them improve their number sense.  However, many have requested more challenging puzzles, so I have included a second more challenging puzzle for older puzzlers (just click the link below). In each, there are 8 statements each corresponding to a number.  You have to use the numbers 0 through 9 once and only once to fill in the correct number for each statement.  You will need to use and develop your deductive problem solving skills in order to correctly place the numbers.  Since there are only 8 answers and 10 numbers (0 through 9), some of the answers will require two digits.

I created an interactive puzzle that will automatically check your answers and provide feedback. I also created a pdf file that can be used in classrooms or with pencils for those so inclined. The goal is to have fun and challenge yourself.

select Check when complete to check your answers

I hope you enjoy these puzzles.  If you find these interesting, Click Here for a selection of more Number Sense puzzles that I’ve created.  I will be adding to the selection over time. Good Luck and pass the puzzles onto others who may enjoy them!

## Tuesday’s Twister #18 – Number Sense (Order of Operations)

October 25th, 2015 by John Lehet

Here’s another Number Sense Puzzle. Today’s puzzle centers around another fundamental skill that gives many students a really difficult time – Order of Operations. This is geared to younger puzzlers to help them improve their Order of Operations skills. As always, let me first give a general introduction. There will be 8 statements each corresponding to a number. You have to use the numbers 0 through 9 once and only once to fill in the correct number for each statement. You will need to use and develop your deductive problem solving skills in order to correctly place the numbers. Since there are only 8 answers and 10 numbers (0 through 9), some of the answers will require two digits. In this puzzle, some of the answers will be negative, that’s no problem, just make sure the digits use 0 through 9 once and only once.

I created an interactive puzzle that will automatically check your answer and provide feedback. I also created a pdf file that can be used in classrooms or with pencils for those so inclined. The goal is to have fun and challenge yourself.

select Check when complete to check your answers

I hope you enjoy these puzzles. If you find these interesting, Click Here for a selection of more Number Sense puzzles that I’ve created. I will be adding to the selection over time. Good Luck and pass the puzzles onto others who may enjoy them!

## SAT Math Blast – #4

September 3rd, 2015 by John Lehet

Here’s the fourth SAT Math Blast for those preparing for the SAT this Fall. The questions are in the Easy/Moderate level and all pertain to Numbers and Operations:

 Topic – Numbers Level – Easy/Moderate Questions – 10

Remember, just select “START” to give it a try. Use the “NEXT” and “PREV” buttons to navigate and when you’ve answered all of the questions, select “COMPLETE”. You’re results will be posted. Also, you will be able to return to any of the questions to review (just select the question number in the results window).

As always, I hope you enjoyed this post. Please pass it onto others who may enjoy and please click LIKE below if you like it! (you need Adobe Flash in order to interactively run the above exam)

## Tuesday’s Twister #13 – Prime Numbers

May 19th, 2015 by John Lehet

“There are three kinds of people: Those that make things happen, those that watch things happen and those that wonder what happened. ” – Agent Garbo (Juan Pujol Garcia)

Prime numbers are everywhere and they are really easy to understand.  There are just two simple rules to follow:

• – a prime number is a positive integer greater than 1
• – a prime number is evenly divisible by only 1 and itself

That’s pretty straight forward.  Many people assume 1 is a prime number, but by definition, it’s not.  It’s important to realize and remember this when dealing with primes.  Also, 2 is the only even prime number, as all other even numbers are divisible by 1, 2 and itself.

Here’s a couple of prime number puzzles to start you off.

puzzle 1: What is the smallest 2-digit prime number in which both digits are prime and their sum is prime?

puzzle 2: What is the largest 2-digit number in which both digits are prime and their sum is prime?

Let’s look at an example number, say 73.  73 is a prime number and it’s digits, 7 and 3 are both  prime.  However, the sum of the digits 7+3 equals 10, which is not prime.  So, 73 will not work for either puzzle 1 or puzzle 2.

Once you solve the first two puzzles, you should have a good handle on prime numbers.  I recommend listing all of the prime numbers less than 100.  To make it a bit more challenging, let’s look at 3-digit numbers.

puzzle 3: List all 3-digit numbers that have prime numbers for all three digits.

puzzle 4: Of the numbers listed in puzzle 3, list the numbers in which the digits sum to a prime number.

puzzle 5: Of the numbers listed in puzzle 4, which of the numbers are themsleves prime?

Let’s look at an example 3-digit number, say 235.  the digits, 2, 3 and 5, are all prime numbers.  However their sum, 2+3+5, equals 10, which is not a prime number (so it doesn’t work for puzzle 4).

Good luck with the puzzles and have fun.

## Tuesday’s Twister #11 – Number Circuits

May 5th, 2015 by John Lehet

“Go fast slowly” – Clarence Stephens

Number Circuits are an original puzzle that I came up with a few years ago.  They are number sense puzzles that require you to arrange a set of numbers in a designated pattern.  I used magic squares as a theme using shapes other than squares. In all, I was able to develop over 200 puzzles all with this same theme.  Fortunately, Mindware liked the puzzles and published two books.  I was pretty excited (and still am).  The books differ in difficulty, although neither set of puzzles are too difficult (although all puzzle are challenging when you can’t solve them!).  Below are four puzzles, two from each book.  I believe they’re representatve of each collection and Number Circuit puzzles in general.  Click each picture to open a full sized pdf image of each puzzle in a new window.

 from Number Circuits A from Number Circuits B

As always, I hope you enjoyed these puzzles. Please pass them onto others who may enjoy them and please click LIKE below if you like them!

MIndware currently has the books for sale for only \$3.95 (that a 69% savings!).  If interested in purchasing either book just click below:

Number Circuits A (Beginner Puzzles)

Number Circuits B (Advanced Puzzles)

## Tuesday’s Twister #3 – Number Sense – Finding Factors

January 13th, 2015 by John Lehet

“Gravity is a contributing factor in nearly 73 percent of all accidents involving falling objects.” – Dave Barry

Here’s another Number Sense puzzles that I first introduced in the December Holiday Puzzles. This puzzle deals with factors of the whole numbers.  The puzzles are geared for younger puzzlers to help them improve their number sense. There are 8 statements each corresponding to a number. You have to use the numbers 0 through 9 once and only once to fill in the correct number for each statement. You will need to use and develop your deductive problem solving skills in order to correctly place the numbers. Since there are only 8 answers and 10 numbers (0 through 9), some of the answers will require two digits.

I created an interactive puzzle that will automatically check your answers and provide feedback. I also created a pdf file that can be used in classrooms or with pencils for those so inclined. The goal is to have fun and challenge yourself.

select Check when complete to check your answers

I hope you enjoy this puzzle. Good luck and pass it onto others who may enjoy them!  If you get stuck and would like the solutions, use the “Contact Us” button and we will reply.  Also, click “Like” below if you like it!

In order to use the interactive puzzle, you need to have adobe flash enabled.

## Holiday Puzzle #12 – Snowflake Puzzles

December 12th, 2014 by John Lehet

Begin doing what you want to do now. We are not living in eternity. We have only this moment, sparkling like a star in our hand and melting like a snowflake.” – Francis Bacon

This is a new puzzle that is an extension of the Kuruko Puzzles that I created. Like Kurulko puzzles, they are similar to Sudoku puzzles.  I call them Snowflake puzzles because of their shape.  Snowflakes are symmetric shapes with six points.   The Snowflake puzzle follows this design.  It is comprised of 42 hexagons (six sided shapes).  There are white and yellow hexagons.  To complete the puzzle you must fill in each of the empty white hexagons.  There are two simple rules to follow:

1. Surrounding each yellow hexagon there are six white hexagons, these must contain the numbers 1 through 6 (each number once and only once)

2. The number in each yellow hexagon is the sum of the numbers in the three white hexagons that point to it (with a black triangle).

Here’s a snowflake puzzle for you to try –   Click here for a pdf file.

If you like the snowflake puzzle, take a look at the book of 100 Kuruko Puzzles that I wrote which is available on Amazon.com.  Good Luck and pass the puzzles onto others who may enjoy them!