Questions tagged [formation-of-numbers]

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

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-2
votes
1answer
196 views

What is the next number in the integer sequence?

What is the next number in the following sequence? 25 27 30 34 39 45 52 60 69 79 69 60 52 45 39 34 30 26 22 18 82 78 74 70 66 67 64 60 65 80 ?
7
votes
1answer
480 views

Two Christmas trees

To each Christmas tree : Put two $+$, two $-$, and two $×$, to the yellow triangles. in a row, there must be different operators (so between $[2,0,1,7]$ all $3$ operators must appear) $A - B$ means $|...
4
votes
1answer
188 views

Numbers in the wheel

Arrange the numbers 3 to 27 onto the wheel using these rules: The modulus of two adjacent numbers must equal with the number between them. Modulus here means the remainder when the bigger number is ...
4
votes
4answers
596 views

Complete numbers on Clock

I have a different kind of clock at my home. Image of Clock: 5 o'clock on this clock means 1 o'clock actually. Display of data in table: Can you complete all the numbers on this clock by finding ...
-5
votes
2answers
120 views

Expressing numbers as sum of two squares and two powers of 2

It has been shown that the smallest integer, greater than 1, that cannot be represented as a sum of two squares and at most two powers of 2 is 535,903. Show how to express 535,902 as the sum of two ...
-2
votes
1answer
368 views

Make numbers 1-31 with 1,9,7,8

I am stuck with some of the solutions. These are rules: Use all four digits exactly once Allowed operations: +, -, x, ÷, ! (factorial), exponentiation, square root, squaring, parentheses Thank you ...
3
votes
1answer
145 views

Another loop of integers with consecutive terms adding to a square

The integers 1 to 50 are placed around a circle in such a way that the sum of any two of them which are adjacent is a perfect square. Of these integers, all but the prime integers were removed. ...
1
vote
4answers
460 views

Finding pattern of numbers

I have this puzzle for adding 2 numbers (Or sequences) Does anyone have an idea about how this addition works? $$ 5+1=9\\3+1=10\\5+2=21\\8+2=23\\9+0=28\\4+3=?? $$
30
votes
1answer
743 views

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 sum of any two of them which are adjacent is a perfect square. Of these integers, the even numbers are then removed. Restore them....
7
votes
6answers
2k views

How can you get 125 from 2,3,4,5,6?

You are allowed to use the four standard operations (+-/*) to get 125, using each of the following digits exactly once: 2, 3, 4, 5, and 6. I came up with an answer, but took me a while; curious to ...
4
votes
2answers
323 views

Find the ? in this grid

Find question mark in this grid with numbers. csv version: 9,6,7,3 2,4,7,6 4,1,5,8 3,0,3,? Hint: You use all numbers to find ? and it is much more simple ...
1
vote
3answers
2k views

Make 38, 44, 46 using 2,3,8,7?

Using BODMAS/BIDMAS* and the numbers and signs 2,3,7,8, (), -,+,÷,× can you make 38, 44, 46. You can only use each number once. I can't figure it out myself Brackets Order Division Multiply Add ...
4
votes
1answer
152 views

Draw out a Battle!

I'm thinking of a number. It's 5 digits long There's a 5 between a 7 and a 2. The second-biggest number is on the far right. The average digit value is equal to the second-lowest digit. The smallest ...
2
votes
2answers
747 views

Mathematical riddle [duplicate]

Part one: You are presented with ten incomplete equations: 0 0 0 = 6 1 1 1 = 6 2 2 2 = 6 3 3 3 = 6 4 4 4 = 6 5 5 5 = 6 6 6 6 = 6 7 7 7 = 6 8 8 8 = 6 9 9 9 = 6 Your job is to fill in mathematical ...
13
votes
2answers
2k views

My colleague gave me a number puzzle

My colleague probably has left work now, he is no longer responding. He gave me this puzzle and asked me to fill in the '?': ...
2
votes
0answers
359 views

Number sequence with two missing numbers 15, 39, 1/8, 1/49, 100, 11, _, _

Given the following incomplete number sequence: 15, 39, 1/8, 1/49, 100, 11, __, __ What are the two missing values?
4
votes
4answers
506 views

Find the smallest positive integer that cannot be made from four 8s, or show it doesn't exist

This puzzle was inspired by one recently posted by @Max. What is the smallest positive integer that cannot be made from four 8s, where bracketing is allowed and the only permitted operations are ...
5
votes
3answers
7k views

Make numbers 1-100 with only four 8s

Make numbers 1, 2, 3, 4, 5,.....100 using only four 8s. You can use multiplication, division, addition, and subtraction. No negatives. You may use exponents. Example: $1 = 8 \times 8 \div 8 \div 8$
9
votes
1answer
457 views

Arrange numbers into the quadrilaterals

Arrange numbers 1 to 14 to the quadrilaterals, such that: The difference between 2 numbers in squares having a common edge or corner is greater than 2. Numbers inside the green quadrilaterals are ...
6
votes
4answers
723 views

MS Excel Die Hard

You are John McLane, and Simon Gruber is back in town. This time he booby trapped 50 nuclear power plants across the US, and sent you a laptop he prepared, along with the following note: Any ...
11
votes
2answers
507 views

An omalonumerophobic's number sequence

Find all seven terms of the number sequence, a1, a2, a3, a4, a5, a6, a7 given that each successive term is exactly twice the value of the previous term no even digits are used in ...
-2
votes
1answer
28k views

Put the numbers 1, 2, 3, 4, 5, 6, 7, 8, and 9 so the total of each row, column and diagonal add up to the same number [duplicate]

Puzzle for grade 11 foundations of mathamatics course thank you in advance for the help
18
votes
1answer
571 views

Investment advice

I'm considering investing my money with a London broker who offers excellent returns. But the only information I can find about the investment are two numerical codes: Deposits: 3.428571428571......
2
votes
5answers
695 views

Self reference is a pain [duplicate]

How many letters do the answer of this puzzle contain? NB: This came across while web surfing. I don't claim any ownership rights.
4
votes
7answers
326 views

Sum of three six digit numbers

This puzzle is a variation of a 3 digit addition puzzle I saw recently. A , B , and C are positive integers between 0 and 9. A,B and C are different integers Six digit numbers formed using A,B and ...
5
votes
3answers
1k views

Make numbers 1-100 using only the digits 2, 0, 0, 0?

I've already found several, the ones I mostly need are 13, 26, 34-40, and 64-85, but I figure it would be interesting to have a record here for other potentially easier/simpler methods.
0
votes
2answers
2k views

Arrange to get sum of 450 when it is added row wise and column wise

I just came across a maths puzzle,where i should get the sum of 9 numbers(multiples of 10) to be 450 both horizontally and vertically in a 9x9 matrix. Picture attached for reference:
-3
votes
3answers
355 views

If 71:64 then 92:? [closed]

This question was in the logical reasoning section of an exam I had recently appeared in. I still have no clue how this is solved. If 71:64 then 92:? The given options are- 25 32 35 ...
5
votes
1answer
258 views

An EMIRP Game/ Puzzle for Prime enthusiasts

As most math enthusiasts know, EMIRPs are Prime Numbers which are also prime numbers when reversed. Like 17 which when reversed to 71 is also a prime number. Here is a Game or Puzzle based on 5 ...
4
votes
2answers
523 views

Uncle's mathematics puzzles after dinner

I was at my grandmother's home for a dinner. With my siblings, after the dinner party, watching a prime time show. One of my uncles, who is a mathematics professor, didn't like and asked us to sit ...
9
votes
1answer
422 views

Prime to Prime change

Change the Prime Number 71549 to another Prime Number 10067 in Five steps by changing one digit at a time. Every time you change the digit the new number must be a Prime Number also. You cannot ...
-6
votes
1answer
2k views

Mathemetic series 1, 3, 6, 10, 15, 21, 28, 36, 45,__? [closed]

I currently looking what will be the next value to 45 as per given series. Is there any specific equation available?
3
votes
2answers
158 views

Complete the equality (medium-hard)

Complete the equality to make it true: 1 1 1 1 1 = 945 Using similar logic, solve for this: 1 1 1 1 1 = 80 Info: You should ...
3
votes
1answer
563 views

Can you find the pattern?

If the following are true: $4+7+2 = 281435$ $7+3+9 = 212781$ $6+2+7 = 121456$ $2+8+5 = 164036$ Then what would the following equal? $8+4+6\ =\ ?$ Can anybody check my work? I ...
-4
votes
1answer
147 views

Find relation between 2 numbers (username and password)

I have a two sets of Usernames and passwords as follows: User --> Password 1456 --> 3473 1360 --> 3377 Now I have to find the password for 1301. Could anyone please help find the relation (it is ...
1
vote
1answer
227 views

Shortest path from one $\to$ ten with a twist - Updated

NOTE: The rules have been updated to cause the nature of the puzzle to be as intended. I will upvote the answer which was given before the change, but I look for both alphabetic and math operations to ...
9
votes
2answers
10k views

Make 10 out of 1, 1, 5 and 8

A friend of mine shared a puzzle with me this evening. Using the numbers 1, 1, 5 and 8 exactly once, and the basic operations (+, -, /, *) and (optionally) parentheses, form an expression which ...
2
votes
2answers
192 views

Hexadecimal = n times decimal

Was explaining hexadecimal numbers to a friend and this made me wonder: "Is there an hexadecimal number x that is a whole number n times its decimal value ?" So for example the hexadecimal number ...
18
votes
5answers
6k views

How to get 5 from 0,0,0 and 1?

Can you use the digits 0,0,0 and 1 each only once in a mathematical expression for the number 5 using only common mathematical symbols with at least 1 mathematical symbol between each number?
11
votes
3answers
1k views

Find the correct math words to equals the intended number

I am testing a new puzzle. I hope the puzzles are intersting. Example: 3 7 7 2 4 = 40 Answer: two(3) hundred(7) divided(7) by(2) five(4) = 40 Rules: Find the correct words. Numbers of letters have ...
14
votes
3answers
1k views

If 6 was 9, or 100 was 64, or M was N

         Now if a 6,          Turned out to be 9,          I don’&...
18
votes
1answer
1k views

New Mathematics forever

This has been (renamed and) refocused on boboquack’s unforeseen solution, which deserves its own puzzle. Right when you thought the good old days of New Mathematics were safely dusted, ...
5
votes
1answer
296 views

Sticking Numbers

Try to figure out the answers from the 2 patterns below. Find all the 10 digits first. Rotate if necessary. A: What is the missing number? [?] [10] [11] [9] [11] B- What is ...
7
votes
1answer
363 views

Arrange numbers to the triangles, so the sums are equal to S

Rules: Arrange numbers from 1 to 11, and each number can appear max twice. The numbers are arranged, so that any 3 numbers which forming an up-triangle sum to the desired number (S). A equal sign ...
4
votes
2answers
155 views

Representation of Mo-roman numerals

This continues the spirit of Mo-roman numerals started by humn What is/are the natural number(s) that has/have the most different representations in mo-Roman numerals and what is the number of ...
13
votes
2answers
481 views

A mo-Roman sampler

    Pluck some relatively easy mo-Roman mini-puzzles while there’s relatively easy pickin’s. What two English words, taken as mo-Roman numerals, form the same number? ...
13
votes
3answers
1k views

How many consecutive integers can you make using only four digits?

In the spirit of the classic four fours, I wonder what's the optimal set of four numbers? Your goal is to make the most consecutive integers using four digits of your choice. Pick four: $0,1,2,3,...
19
votes
2answers
979 views

Self-intro to mo-Roman numerals

Here come mo -Roman numerals — just like Roman numerals, only mo’ so.   (Explained as we go.)   What number can spell itself in two different ways ...
26
votes
6answers
23k views

The 10,958 Problem

Here is the task: Write down 10958 using all 1-9 digits in ascending order and only one time. You are allowed to: 1) group digits into numbers 2) use 5 basic operations: + - * / ^ ("^" ...
-6
votes
4answers
204 views

Find 25 using 6, 25, 9, 8 only

You can only use these numbers once, so not square root or cubed root or anything else. Good Luck!!