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For puzzles about forming numbers using other numbers and mathematical operations.

4
votes
1answer
78 views

A Math Puzzle with a Pattern

Inspired from a puzzle marathon, here is a math puzzle. There is a pattern with this set of numbers (not in the creation though). According to the pattern, what is the logical replacement for the ...
9
votes
1answer
267 views

Form the biggest squaring number

You are going to start from any number with distinct digits lower than four digits (such as $a$, $ab$, $abc$) and you will apply the rule below: Take the square any number you want in the number (you ...
3
votes
2answers
724 views

make this sum using only +

A bit of a speed question this, first correct answer gets the check. Although you are allowed to use computers, it might be quicker not to. By placing only $+$ signs between some of the numbers on the ...
4
votes
2answers
593 views

Use 2, 0, 1 and 8 to make 71

Use all and only the digits $2,0,1,8$ once each to make the number $71$. Allowed operations; anything not on this list is banned: $+,-,\times,\div, ()$ (parentheses and/or choose function) ...
14
votes
6answers
2k views

Use 2 0 1 and 8 to make 67

Use $2$ $0$ $1 $ and $8$ to make the number $67$ RULES You must use all 4 digits. Only the digits 2, 0, 1, and 8 can be used. You can make multi-digit numbers out of the numbers. Examples: 20, 82, ...
6
votes
8answers
458 views

Make $1,\dots,15$ using $3, 9, 9, 9$

This was inspired by many puzzles that use three/four numbers to create other numbers. I chose these numbers in particular because of this post. Can you find a way to make all the natural numbers ...
7
votes
3answers
195 views

Is this number unique?

Inspired by Interview Question or Pathbreaking puzzle and A121808. Start with $1$, and count the number of times $1$ occurs, and report this in the format 'number of ones:1', i.e. the next term is $...
15
votes
7answers
3k views

Make 4 4 4 4 = 30,31

Follow up question to Make 5 5 5 5 = 19 Can you find a way to make: $4\ 4 \ 4 \ 4 = 30$ and $4\ 4 \ 4 \ 4 = 31$ by adding any operations or symbols on the left side of the equations? You can ...
10
votes
6answers
2k views

Maximize the number of factorials in your solution to 6 5 4 3 = 1

Using the same rules as Make 6 5 4 3 = 1, but maximize the number of factorials. You may not take the factorial of 1 or 2. This is harder than it looks. A great answer has six factorials, an ...
11
votes
12answers
7k views

Make 6 5 4 3 = 81

Can you find a way to make: 6 5 4 3 = 81 by concatenation and/or adding any of (and only) these mathematical operators: + - × ! ÷ ^ standard parentheses () You cannot add other numbers to the ...
4
votes
9answers
939 views

Make 6 5 4 3 = 1

Can you find a way to make: 6 5 4 3 = 1 by concatenation and/or adding any of (and only) these mathematical operators: + - × ! ÷ ^ standard parentheses () You cannot add other numbers to the ...
22
votes
10answers
13k views

Make 5 5 5 5 = 19 [closed]

Can you find a way to make: $5\ 5 \ 5 \ 5 = 19$ by adding any operations or symbols? You can use only these symbols: $+,\ -,\ *,\ !,\ /,\ \hat\, ,\ ()$. It is limited to this list, and ...
-5
votes
1answer
117 views

Making 49 from 5, 1, 3, 4 [closed]

I have these numbers: 5, 1, 3, 4. There are four different ways to make 49 - what are they?
1
vote
1answer
62 views

Find the operators

Assume you are using a basic calculator and press these numbers in order. Replace each question mark with plus, minus, multiply and divide may be used, but no sign should be used more than once. In ...
6
votes
1answer
81 views

The Yerata number system

There are only a few words for numbers in the Yerata1 language. Here are all of them, in random order: imu tere nuopo rowintom rowintom rowintom imu tere nuopo re nuopo rowintom re nuopo nuobo imu ...
17
votes
4answers
1k views

A mazegic square

So you like mathematical diversions? Here's something new for you then ...
5
votes
3answers
389 views

Use 2,3,4,5 to get 26 using only + - * /

Use 2,3,4,5 and + - * / only once each (it's not necessary to use all of them) to equal 26. I know 2 answers, but there is a 3rd (or more) :)
4
votes
1answer
233 views

A challenging Magic Square

Find a 3x3 Magic Square where each row, column and both diagonals result in positive number 9 You are allowed any of the 4 math operations : add, subtract, multiply or divide. NO OTHER OPERATIONS ...
3
votes
2answers
254 views

When is my date of birth?

___4,_4,_4 This is my real date of birth, because it looks unique, I try to do a simple operation, and I get a number 222. In fact it is able to solved without looking at the hint, but I'm trying to ...
0
votes
2answers
212 views

Factor the number 23 into four numbers $a + b \sqrt{2} + c \sqrt{3} + d \sqrt{6}$ [closed]

We know that $23$ is a prime number nonetheless, I'm asking to find 4 numbers $a,b,c,d > 0$ such that $23$ factors. $$ 23 = A \times B \times C \times D \text{ with } A,B,C,D = a + b \sqrt{2} + c \...
1
vote
8answers
3k views

Make numbers 1-30 using 2, 0, 1, 9

This is very similar to the 2, 0, 1, 8 problem. Just try to make all numbers 1-30 using the digits 2, 0, 1, 9. Rules: Use all four digits exactly once Allowed operations: +, -, x, ÷, ! (factorial), ...
8
votes
4answers
3k views

Get 59 from 1,9,4,8 in order [closed]

I’m stuck on trying get $59$ by the numbers $1,9,4,8$ in order. I have no idea if it’s possible, I made it for 1-70 just not 59. I made it without order: $(-1+8)*9-4$ You can use not only the basic ...
-2
votes
2answers
210 views

Making 30 using 3 3s [closed]

Hope that all can answer the question. It's an IQ! How can one make 30 using 3 only three times?
-6
votes
4answers
254 views

find out the missing expressions [closed]

10 10 10 10 = 1 10 10 10 10 = 2 10 10 10 10 = 3 10 10 10 10 = 4 10 10 10 10 = 5 10 10 10 10 = 6 10 10 10 10 = 7 10 10 10 10 = 8 10 10 10 10 = 9 10 10 10 10 = 10 You can only add ...
12
votes
2answers
557 views

Ode to convergence

Taking a numeral core (digits: a non-quad four) digits I ordered, then lesser I minused, till evolve I couldn't more. What is this unfathomably clunky poem all about?
4
votes
3answers
261 views

Puzzling Number Boxes

Found this puzzle as a translation question. The Chinese is fairly simple, it just asks to solve for the ? in the bottom right square. The actual puzzle though, I have no clue about. Can any of you ...
-4
votes
1answer
239 views

What is the smallest counting number you can create higher than 1? [closed]

What is the smallest integer you can create using 1,2,3,4,5,6,7,8,9 that is strictly greater than 1? You can use any mathematics symbol. You must use all nine numbers. You can't use the same number ...
4
votes
2answers
273 views

Numbers and Countries

The relations given below. According to these values, solve the last relationship. Germany - Kenya = 7 Mexico - Brazil = 9 Turkey - Australia = 18 Norway - Ghana = 7 Korea - ...
7
votes
2answers
1k views

Pick seven numbers so that every operation gives same result

Pick seven numbers so that every operation (addition, subtraction, multiplication, but not division) gives the same result. For subtraction, you may take the result's absolute value. Numbers cannot ...
5
votes
3answers
2k views

Mathematics IQ puzzle, solving puzzle by looking at neighboring digits [closed]

Can anyone solve this puzzle? I have tried many times but I could not find any symmetry or sequence. \begin{array} {|c|c|c|} \hline 3&25&5\\ \hline 16&9&6\\ \hline 125&36&18\\ ...
8
votes
1answer
822 views

IBM Research Puzzle – 5-ops implementation of erasure code

I found this interesting puzzle on IBM Research Puzzling Page called Ponder This; specifically, here. Design a storage system that encodes 24 information bits on 8 disks of 4 bits each, such that: ...
1
vote
1answer
117 views

What is the relation between these numbers?

Based on the relation between the numbers of each shape, find the number for the question mark. 337 339 549 569 Source: Iraninan Ph.D University Enterance 2017
2
votes
9answers
1k views

How to use the numbers 3, 5, 6, and 7 to get 100? [closed]

Any mathematics symbols and processes to use the numbers 3, 5, 6, and 7 once each to get 100.
5
votes
1answer
323 views

What is the minimum number of digits required to make the numbers 1-20?

What is the minimum number of digits required to make the numbers $1-20$? Any $n$ consecutive numbers can be counted as a $n$-digit consecutive number. So, $$12\\34$$ has the numbers $$1, 2, 3, 4, ...
5
votes
2answers
446 views

Make 439204 from Φ (Golden Ratio)

In my last formation-of-numbers question I somehow tricked myself, because I wanted to make a puzzle about a number that looks like a year. But the complicated solution I thought of turned out to be ...
13
votes
5answers
3k views

Make 2008 from Φ (Golden Ratio)

I know that questions of the form "Use [arbitrary set of numbers] to make 2018" seem to be not very well recieved in the last days. That's why this puzzle is about making 2008. But instead of using ...
7
votes
3answers
214 views

Integers around a circle with consecutive pairs differ to a square

Inspired by this puzzle : Integers around a circle with consecutive pairs adding to a square The integers 1 to 50 are placed around a circle in such a way that the difference of any two of them which ...
8
votes
4answers
1k views

Use four 8's to make the number 2016

Previous question: Use two 2's, two 1's, and two 8's to make the number 2018 Background: I was trying to add some new elements (hopefully creative and interesting) to this traditional type of number-...
12
votes
5answers
4k views

Use two 2's, two 1's and two 8's to make the number 2018

This is another number formation question. You must use each of $2$, $1$ and $8$ exactly twice to make the number $2018$. The rules are Allowed symbols: $+$, $-$, $\times$, $\div$, $($, $)$, $\sqrt{\...
3
votes
0answers
185 views

Find the combination algorithm for 16 digit numbers [closed]

Find the combination algorithm for numbers that will be generated. And the numbers are: 0535 8549 9933 3564 0500 7197 6709 9534 0531 3170 7802 8731 The numbers ...
0
votes
3answers
4k views

10 9 8 7 6 5 4 3 2 1 = 2018

Add the four basic operators × ÷ + −: 10 9 8 7 6 5 4 3 2 1 to get the total 2018. Keep the order; do not combine numbers. Don't use any brackets. Use all four operators at least once.
-6
votes
2answers
2k views

Make numbers 33-100 using only digits 2,0,1,8

Use the numbers 2, 0, 1, and 8 (ALL of them...only ONE time each) to make every integer from 33 to 100. Allowed operations: +, -, x, ÷, ! (factorial), exponentiation, square root and Parentheses No ...
4
votes
8answers
3k views

How to use 2,0,1,8 to make 51? [closed]

How to use the number 2,0,1,8 to make 51? You can use any operation except for multiple factorials and you can concatenate numbers, ex.2,0=>20 You can take the square root of a number without a ...
6
votes
4answers
2k views

Can you make 2 0 = 1 5? [closed]

Can you find a way to make 2 0 = 1 5 by adding any operations or symbols? You can use symbols such as these: +, -, *, !, ^, (). It is not limited to this list.The symbols may be added either between ...
41
votes
10answers
21k views

Can you make 1 1 1 1 = 5? [closed]

Can you find a way to make 1 1 1 1 = 5 by adding any operations or symbols? You can use symbols such as these: +, -, *, !, ^, (). It is not limited to this list. Good Luck! P.S. You can not add any ...
9
votes
2answers
7k views

Is Ron a mathematical prodigy?

I and Ron were talking casually over coffee. Just then a thought sprung into my mind; could there exist numbers such that if their digits are reversed, for example $123\to321$, the new number is ...
-5
votes
3answers
173 views

Get 20160 with 5 2's and any Mathematical Operator [closed]

Here is a mathematical riddle: Find a way to get 20160 with 5 2's and any mathematical operators you want. Have fun! Don't forget that I said any. Feel free to look online for crazy whacky math ...
2
votes
2answers
1k views

Make numbers 93 using the digits 2, 0, 1, 8

I have a 1 to 100 building challenge with 2, 0, 1, 8, all made but 93 is not made. I need your help! This is similar to the "Four fours" puzzle, but using the digits 2, 0, 1 and 8. Rules: Use all ...
21
votes
6answers
30k views

Make numbers 1 - 30 using the digits 2, 0, 1, 8

It's 2018 so let's repeat last year's challenge with new digits. This is similar to the "Four fours" puzzle, but using the digits 2, 0, 1 and 8. Rules: Use all four digits exactly once Allowed ...
3
votes
1answer
111 views

From the information given below- prove that Z = 4561

If- ONE * THREE * FIVE = 225 NINE * SEVEN + TWELVE = X 225 + X = Y 10,18,32,56,93,146,? ? + Y = Z Prove that, Z = 4561