Questions tagged [formation-of-numbers]
For puzzles about forming numbers using other numbers and mathematical operations.
331
questions
1
vote
9answers
383 views
Use numbers 1-9 to yield 300000
Inspired by @Saiid's earlier question.
Using $+,-,×,÷,$ exponents and factorials, use all the numbers $1-9$ (once and only once each) to generate $300 000$.
Don't compose numbers from their digits, ...
1
vote
2answers
2k views
$7777/6666 = -212$
The title explains it pretty much, make $7777/6666$ equal $-212$. The following operators can be used.
$+,-,*,/,\hat{},()$
Rules:
Each number can only be used once
You can move the numbers around ...
6
votes
18answers
5k views
Use the numbers 1-9 to equal 1150 [closed]
Not sure if this is too hard, but it's a more or less simple math puzzle. Use the numbers
$1,2,3,4,5,6,7,8,9$
to get an answer of 1150. You can use the operators
$+,-,*,/,\hat{}$
You can use ...
6
votes
4answers
718 views
(addition) 7 point star / heptagram
Place the numbers $1$ through $14$ onto each point, so that:
A = 1
The sum of points in every line are equal,
(A+I+J+C = B+J+K+D = C+K+L+E = D+L+M+F = E+M+N+G = F+N+H+A = G+H+I+B)
A+B+C+D+E+F+G+1 = H+...
0
votes
10answers
1k views
Get 6 6 6 6 to equal 58 [closed]
$6 6 6 6 = 58$
$+ - * /$ and $()$ only
58 must remain as 58, (not 5 + 8, etc.)
3
votes
2answers
2k views
Finding the largest 7-digit number
Find the largest 7-digit number without its digits repeating, such that the number is divisible by all of its digits
I found some constraints:
• 0,4 and 5 cannot be included
• The number found should ...
3
votes
2answers
279 views
Find a Strobogrammatic number, so if we square it, the result is a pandigit number
Find a Strobogrammatic number,
so if we square it, the result is a pandigit number.
Note :
A Strobogrammatic number is a number when typed on a calculator, and the calculator is spun 180 degrees, ...
3
votes
1answer
519 views
Find the rule : triplet number into Positive Integer
These are triplets of numbers into positive integers:
...
5
votes
4answers
1k views
Making 1-50 from 2016
Make the numbers 1-50 using the numbers 2 0 1 6 in the given order.
1.You must use all four digits.
2.You may not use any other numbers.
3.You may use +, -, x, ÷, square root, squaring and cubing, ...
40
votes
16answers
5k views
What is the smallest set of letters that can spell any integer? [closed]
Today my 9-year-old nephew told me that he can spell any integer in English using only 9 letters. This is how he's doing it:
...
1
vote
2answers
234 views
modified 3x3 panmagic squares
This is a modified 3x3 panmagic squares.
The square is divided into 2 triangles.
Numbers 1 to 9 is arranged to upper triangles.
Numbers 10 to 18 is arranged to lower triangles.
All rows, all columns, ...
5
votes
1answer
631 views
Check digit number : Find the maximum number of distinct ways
Find the maximum number of elements in a set containing combinations of three digits (from 0 through 9) with the following rules:
Each digit can be used more than once.
Any two combinations in the ...
4
votes
2answers
307 views
The mathy square strikes back!
This is a follow-up question to Does this mathy square have any solutions? (And how many?).
Consider a 7x7 grid of math operators o and numbers ...
14
votes
4answers
1k views
Does this mathy square have any solutions? (And how many?)
Consider a $5\times5$ grid of math operators and numbers that encodes 8 math equations:
A + B = C
= + + + +
D + E = F
+ = = = =
G = H + I
There are 3 horizontal ...
-2
votes
3answers
697 views
Can you express 1844 in a curious way? [closed]
Can you find integer values for $p$ and $q$ with $p,q\in\{0,1,2,\ldots,9\}$ so that the following equation holds?
$p^q - q^p = 1844$
5
votes
2answers
519 views
Reveal all five equations
Five men enter a bar.
1st man order 1 Pepsi and 1 Cocacola
2nd man order 2 Pepsi and 1 Cocacola
3rd man order 3 Pepsi and 1 Cocacola
4th man order 4 Pepsi and 1 Cocacola
5th man order 5 Pepsi and ...
2
votes
2answers
337 views
It is related to a type of mathematics game
Start with two digits from $1\dots9$ to form a $2$-digit number.
Multiply this number by a single digit from $1\dots9$.
Add the result to another two digit number from $1\dots9$, and calculate the ...
5
votes
1answer
2k views
Expressing numbers using 0, 1, 2, 3, and 4
The least number that cannot be written using the numbers 0, 1, 2, and 3, each exactly once, and any combination of standard arithmetic operations (including factorials) is 41. What is the least such ...
4
votes
3answers
329 views
Number wheel Challenge!
Much like the Word-tank-wheel challenge, but numbers!
Find a number that can 'rotate' in a way that the origin number and its rotations must be divisible (i.e. whole number) by the number of times it ...
5
votes
4answers
514 views
Find the next number in the sequence [closed]
One tough puzzle to solve :
Find the next number in the sequence :
5,105,74,712,37,?
Options are :
a. 2008
b. 57
c. 507
d. 98
e. 44
What is the next number, and why?
Puzzle ...
13
votes
2answers
619 views
Help me find my friend!
I need your help! My friend has gone missing and I have no clue where he could be! However, he did manage to get a message out to me:
Kidnapped. Send help. I am here:
port town. $\left\lfloor\sqrt{\...
10
votes
3answers
1k views
Two functions that can't be applied in different order to arrive at same result
Here's my puzzle:
Write two unary functions f, g and provide an input x so that only the ...
-5
votes
4answers
444 views
A Wonderfully Tricky way of Making any Positive Integer [closed]
Make all positive integers, starting from $1$, using:
Exactly four $4$'s (and no other digit), concatenation being allowed,
Any standard mathematical symbol(s) and operation(s) not listed below.
...
28
votes
11answers
6k views
Make 11 from five identical digits
At a tender age my father introduced me to an arithmetic game: making the number 11 from five single digits using only the basic operators listed here:
...
34
votes
21answers
12k views
3:3! It's a football score! [closed]
Given to me, by a friend:
How would you make 20, using two threes?
You may use any basic operation. And others, such as square roots (the symbol), factorials, etc. Any operation is allowed.
Just ...
1
vote
1answer
575 views
Riddle with functions [duplicate]
The following is a riddle, that is not so easy as it seems.
Using the numbers 1, 3, 4, 6 only once, you must use any of the functions (addition, multiplication, division, subtraction) in order to form ...
11
votes
2answers
335 views
Make a certain number with an unusual calculator
The Kasio Kool-Kalk™ is a poorly-designed calculator with only two buttons, labelled $[A]$ and $[B]$.
Pushing $[A]$ replaces the currently displayed number $x$ with $2-\frac{1}{x}$.
Pushing $[B]$ ...
7
votes
2answers
573 views
Please make x and y and z
This puzzle continues "Please make 1 and 2 and 4".
A mathematical expression is feasible, if it obeys the following rules:
Any real number may be used
One may use brackets "(" and ")" to structure ...
0
votes
1answer
1k views
24 game… with exponents!
You may have seen the 24 game where you take four numbers and try to make 24 using the numbers and mathematical operations. However, I present a twist on the 24 game: with an exponent. Here are the ...
14
votes
1answer
2k views
Hello, I am a pretty big number. Add a line to make me many things
I am a pretty big number:
Here are a few challenges for you:
Add a line to make me a millennium.
Add a line to make me a millennium and ten.
Add a line to make me a century and one.
Add a line to ...
1
vote
4answers
931 views
Use six 6s in an expression that equals 1,000
Given: six 6s
Goal: Construct an expression with value $1,000$
Rules:
Use all six digits in each expression.
No other digits are allowed.
Concatenation of digits is allowed.
One horizontal ...
9
votes
3answers
3k views
A breathtaking way of making every possible positive integer
This is a follow-up question to my older puzzle "A truly amazing way of making the number 2016" and to my other older puzzle "A truly amazing way of making every possible positive integer". My ...
0
votes
3answers
264 views
Fill in the parentheses [closed]
$()+()+()+()+()=30$
How can you fill in the parentheses with the numbers $1, 3, 5, 7, 9, 11, 13$ to make the above equation true? Repeats are allowed, but you must fill in all of the parentheses!
...
7
votes
5answers
1k views
Simple but interesting math puzzle [duplicate]
Four numbers are available: $1$, $3$, $4$ and $6$. Every number must be used once and only once with (some of) the operations $+$, $-$, $\times$, $\div$ to form the number $24$.
It's from the book "...
7
votes
4answers
2k views
A truly amazing way of making every possible positive integer
This is a follow-up to "A truly amazing way of making the number 2016":
For every positive integer $n$, find a mathematical expression that
yields the value $n$ while obeying the following rules:...
13
votes
16answers
10k views
A truly amazing way of making the number 2016
Find a mathematical expression that yields the value $2016$ while obeying the following rules:
Each of the digits $1,2,3,4,5,6,7,8,9$ is used exactly once
Decimal points are allowed
You ...
2
votes
2answers
409 views
90s Number Puzzle
So here's how it works: Take the digits from 1991. You can use the digits in any order, only once (you can't make a 19 or 91), with any operation sign to get answers between 1-100. For example: $4=(1+...
-1
votes
2answers
163 views
Form n/2 with n amount of ANY number
For every $n, m \in \mathbb{N}; n,m > 1$, construct a method to produce $\lfloor\frac{n}{2}\rfloor$ using n ms.
You can use:
$$x+y$$
$$x-y$$
$$x*y$$
$$\frac{x}{y}$$
$$x^y$$
$$x\bmod y$$
$$\sqrt[k]{...
12
votes
8answers
2k views
Make 1 with any 3 of the same numbers
Is it possible to make 1 with any 3 numbers, all the same, such as using 3, 3 and 3 or 6, 6 and 6?
Can you think of a proof which will work no matter which number it is?
Trig functions allowed.
29
votes
9answers
5k views
How many consecutive positive integers can you make using exactly four instances of the digit '4'?
Starting at 1 (which is 4 - $\sqrt4$ - 4/4), how many consecutive integers can you make using exactly four instances of the digit '4'?
Basic rules:
Any operator symbol is "free".
Any printed '4' ...
0
votes
11answers
3k views
Make the number 17 using only 2, 3, and 4 [closed]
Is it possible to make the number 17 using only 2, 3, and 4?
Using the numbers only once and any operation, including factorials and other more advanced math.
And it would have to be exactly 17.
-5
votes
3answers
2k views
Make 82 With Numbers and Dots
How do you make 82 with the numbers
$4, 5, 6, 7, 8, 9, 0$
and 8 dots.
Get creative! You can use any mathematical operation, and the dots can be used in any mathematical way.
No ratios.
You must ...
12
votes
3answers
677 views
Who will find the number on their own hat first?
Both $A$ and $B$ have numbered hats on their heads. $A$ and $B$ both cannot see his/her own hat, but they can see other one's hat. $A$ sees number on $B$'s hat as $5$ and $B$ sees $A$'s number as $4$. ...
7
votes
5answers
9k views
Alternating numbers
Alternating numbers are numbers in which all digits alternate between even and odd. For example: 2703 and 7230 are alternating ...
2
votes
1answer
155 views
decipher this modified sum operation,
This is crossposted from Math.SE, the original question is here
$1+2+3+4 = 61$
$2+3+4+5 = 52$
$3+4+5+6 = 51$
$4+5+6+7 = 50$
$7+8+9+10 = ?$
29
votes
13answers
14k views
10 9 8 7 6 5 4 3 2 1 = 2016
Add the four basic operators $\times\div+\,\;-$ and optionally brackets to:
$10 \quad 9 \quad 8 \quad 7 \quad 6 \quad 5 \quad 4 \quad 3 \quad 2 \quad 1$
To get the total $2016$.
Rules:
We are ...
-7
votes
5answers
310 views
Largest number with two hands [closed]
Pretty short one, really.
Given your two hands, what's the largest number you can represent?
Some example representations:
1 finger on each hand: that's 2.
2 fingers on one hand, and 3 on the other: ...
-3
votes
2answers
2k views
Fill in the operators to make $7 \circ 8 \circ 7 \circ 7 \circ 8 \circ 3 = 100$
With the given numbers I need to make:
$7 \circ 8 \circ 7 \circ 7 \circ 8 \circ 3 = 100$
Using only the following operators:
$+\space-\space\times\space\div$
3
votes
0answers
314 views
How is it possible to make 8 (…) 8 (…) 8 = 6? [duplicate]
$$8\text{ }8\text{ }8 = 6$$
Add in any required number of mathematical symbols to make the above equation work.
How is this possible? Can somebody explain?
4
votes
2answers
200 views
Autonumerograms
An autonumerogram, or self-enumerating number, is a number that can be read as describing itself by providing a pairwise inventory of its own digits. For example, 22 (two 2's) and 14233221 (one 4, two ...
