# Questions tagged [mathematics]

A puzzle strongly related to mathematical facts and objects, or whose solution needs serious mathematical arguments. General mathematics questions are off-topic but can be asked on Mathematics Stack Exchange.

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### I am caught when I was about to steal some candies

I am a eight years old boy, I love candies, but my mom does not want me to eat any more candies because I start to have black teeth :( but I still love candies so... Today when I was about to steal ...
2answers
298 views

### Pan Digital Lucky Seven wants you to figure out all the digits

$Given$: A, B, C, D, P, Q, R, S, T are distinct digits varying from 1 to 9. AB, CD, PQ, RST are all concatenated Numbers. From the given expression , figure out all the digits to make lucky seven. ...
4answers
2k views

### Savage Road Signs

There is a highway that starts in the city of Savage. You must must place distance marker signs on this highway for the outgoing traffic. According to highway code, there must be a distance marker ...
2answers
138 views

### sum and gcd june19 challenge!

Can anyone please help me out with the https://www.codechef.com/JUNE19B/problems/SUMAGCD question? Chef has a sequence of positive integers $A_1,A_2, \dots, A_N$. He wants to split this sequence ...
3answers
197 views

### Find the Missing Members of this Powered Sequence

There are 4 missing members in this small series...labeled ???. Hint 1; Hint 2: Complete the series. $191$, $426$, $931$, $???$, $???$, $646$, $971$, $???$, $???$
4answers
3k views

### Use 1 9 6 2 in this order to make 75

I'm looking for a solution to make number $75$ with numbers $1$ $9$ $6$ $2$ in that order and the same rules as in Use 2 0 1 and 8 to make 67. Here a copy of those rules: You must use all 4 digits. ...
2answers
155 views

### Please figure out this Pan digital Prince

Given: P, R, I, N, C, E, T, O, M are all distinct digits varying from 1 to 9. PCRON, PRINCETOM are two concatenated numbers. PCRON is the highest possible number you can have fulfilling the ...
2answers
527 views

### 2019 gold coins to share

You and your friend has found in total 2019 gold coins in a treasure hunt. Since your friend found the place to dig up, he deserves a bit more gold than you so you offer a game to share the coins to ...
3answers
134 views

### Make 2019 Factorial Multiplication a perfect square

N is not a square number and consists of 2019 factorial multiplication as shown below: $N=1!\times 2!\times 3!\cdots 2018!\times2019!$ At least how many factorial needed to be removed from the ...
2answers
1k views

### Finding numbers having exactly two distinct digits

We have $10^K$ road signs (numbered 0 through $10^K−1$). For each valid $i$, the sign with number $i$ has the integer $i$ written on one side and $10^K−i−1$ written on the other side. We need to ...
1answer
128 views

### Don’t let this daunting equation dissuade you to deduce the desired result

Given: A, B, P are distinct digits. AA, AAA, ABB are concatenated numbers. Relations: $$P=A+A+B$$ $$(AA + ABB)^P-(ABB)^P=(AAA - A) ^P+(B+B^B*B)^P+(B^B)^P$$ Don’t be afraid to make reasonable ...
1answer
2k views

### Finding Round Integer

An integer is round if it is greater than $0$ and the sum of its digits in decimal representation is a multiple of $10$. Find an optimal procedure to compute the $N^\text{th}$ smallest round integer. ...
1answer
177 views

### A Diophantine rational function [closed]

For how many integers $N$ is the rational function $\frac{N^2-2N-15}{N^2-N-12}$ also an integer?
2answers
443 views

### Let M and N be single-digit integers. If the product 2M5 x 13N is divisible by 36, how many ordered pairs (M,N) are possible? [closed]

Let M and N be single-digit integers. If the product 2M5 x 13N is divisible by 36, how many ordered pairs (M,N) are possible? -- source I tried it by reducing 36 into its positive factors (1,2,3,...
1answer
219 views

### Mathematical Sequence Based on Prime Numbers

This sequence is based on prime numbers Hint 1: 16, 17, 11, 16, 10, 8, 13, 7, 14, 8, 11, 7, 5, 10, 4, 11, 5, 10, ?, ?, ? What are the final three numbers?
0answers
182 views

### Magical Evening

Tonight will be a magical evening full of fun and excitement if you can figure out this riddle. When the clock strikes nine but loose three dash you will find a feast at the seven of these. Where ...
3answers
227 views

### From the given Square - Factorial Relationship, deduce the unknowns

$Given$: A, B, C, D are distinct digits and can vary from 1 to 9. DB is a concatenated number. From the following relationship, solve for A,B,C,D. Give your deductive reasoning. Please read all ...
2answers
562 views

### Find the Factorial From the Given Prime Relationship

$Given$: $P$, $Q$, $R$ are three distinct Prime Numbers $P!$ = $Q$ x $R^Q$ x $P$ Find P, Q, R.
9answers
4k views

### Winning Strategy for the Magician and his Apprentice

There are $13$ upside-down opaque cups and $2$ balls, a magician and his apprentice and yourself. You decide under which cups to put the balls, and the objective of the magician is to find the two ...
1answer
208 views

### Deduce the Component Digits from these three Sets of Symmetric Power Relations

Use calculator to the minimum. Under Logical Deduction, these Daunting Relations will quickly melt away to reveal the constituent digits. All three sets show beautiful symmetric Relations with first ...
5answers
354 views

### Shortest time to meet

Three runners are located at the corners of an equilateral triangle, 100 meter a side. They run to a point inside the triangle and their goal is to do it as fast as possible. If they run at the same ...
1answer
347 views

### Why is “D” the Center of “Attention” at this Circular Conference

All the Alphabet Guests are seated according to their order at a unit distance apart around this circular conference table. Why is “D” the center of “Attention”?
1answer
99 views

### Devil goes Pan Digital..Sometimes Lucky..Sometimes not..Figure him out

$Given$: D, E, V, I, L, G, N, O, T are distinct digits (1 to 9). $D+E$ brings good luck $I+L$ is unlucky $N+O-T$ is unlucky too. $DDDD$ = $(D+E)^V$ + $(I+L)^G$ + $(N+O)^T$ Fully Figure out ...
1answer
147 views

### What is next: 2, 3, 5, 13, 89, 233, …? [closed]

Based on what is shown, what is the next number in the sequence?
5answers
154 views

### 3 as a Sum of 3 Pan Digital Expressions [closed]

$Given$: $3$ = { A } + { B } + { C } Where A, B, C represent 3 unique Pan Digital Expressions. Each contains all the digits 1 to 9 occurs only once. Expressions contain only plus, division ...
1answer
165 views

### Starting with e and Pi…how do you get to Phi? [closed]

No equations...need one line answer only. No tricks here.. $e$, $\pi$, $\phi$ are regularly used universal constants. Here is the one line answer: If you want, you can do more to improve accuracy ...
2answers
2k views

### Diet Coke or water?

At PuzzlingCorp, all employees have a break at 10:00am sharp every day, and immediately proceed to get either plain water or a diet coke. The people at PuzzlingCorp are also highly susceptible to ...
1answer
74 views

### Express 2222 as a sum of 3 powers in 2 Different Pan Digital Expressions

Solve for the digits in this Unique set of Palindrome- Pan Digital Expressions: $2222$ = $(A/B)^C$ + $(D/E)^F$ + $(G/H)^I$ $2222$ = $(A/B)^I$ + $(D/E)^F$ + $(G/H)^C$ Where, A,B,C,D,E,F,G,H,I ...
2answers
63 views

### Rep Digit Palindrome expressed as a Unique set of Pan Digital Relations

Allowed Operations: Addition, Subtraction, Multiplication, Division, Exponentiation. Right and Left Bracket use permitted. Express $2222$ In $2$ Different ways using all the digits 1 to 9 only ...
3answers
120 views

### Express the Squares of first 20 Numbers with only numbers found in their Sum of Digits

Allowed Operations ...Addition, Subtraction, Multiplication, Division, Exponentiation, Simple Factorial. Left and Right Brackets allowed. Expression should involve minimum number of total characters: ...
6answers
829 views

### Restoring order in a deck of playing cards (II)

Michelle has a deck of 52 playing cards in a pile with their backs facing up. She takes the first 2 cards in the pile, turns them over, and places them at the bottom of the pile. She now takes the ...
1answer
200 views

### Make a formula to get the highest score

In this puzzle you need to obtain the highest score with the following rules 1) choose two digits from 1, 2, 3, 4, 5, 6, 7, 8 and 9. These digits are represented by two letters, let us say $T$ and $M$...
2answers
479 views

1answer
75 views

5answers
324 views

### How to Modernize Student Council

You are the math teacher at a high school and you are in charge of organizing Student Council for the whole school next year. Your boss, the Principal, read a research paper on Student Councils and ...