User JMoravitz

44 votes

Why is $\{\{1\}\}$ not equal to $\{1,\{1\}\}$?

discrete-mathematics elementary-set-theory

answered Jul 16, 2016 at 2:07

39 votes

Accepted

Why does $3^{16} \times 7^{-6}$ become $\frac{3^{16}} {7^{6}}$?

algebra-precalculus exponentiation

answered Nov 3, 2017 at 0:53

36 votes

Accepted

Perfect square all 9's

number-theory

answered Oct 5, 2015 at 1:47

30 votes

Can a relation be both symmetric and antisymmetric; or neither?

elementary-set-theory relations examples-counterexamples

answered Oct 11, 2015 at 21:12

29 votes

Accepted

Weakly Connected Graphs

graph-theory connectedness

answered Dec 18, 2014 at 17:35

29 votes

Accepted

Expected value of the number of flips until the first head

probability

answered Mar 19, 2015 at 3:33

28 votes

Accepted

How to compose two functions?

algebra-precalculus functions

answered Mar 19, 2017 at 3:20

27 votes

Is $n^7 - 77$ ever a Fibonacci number?

algebra-precalculus number-theory elementary-number-theory contest-math fibonacci-numbers

answered Jul 7, 2016 at 17:23

26 votes

Accepted

Two players placing coins on a round table with the goal of making the last move

recreational-mathematics

answered Nov 20, 2015 at 15:13

24 votes

Accepted

What is the Scientific Notation of Zero?

algebra-precalculus notation arithmetic number-systems scientific-notation

answered Dec 21, 2014 at 4:00

23 votes

Accepted

Why aren't these two solutions equivalent? Combinatorics problem

combinatorics discrete-mathematics problem-solving

answered Apr 22, 2019 at 19:13

23 votes

Accepted

Smallest number such that the sum of digits and the product of digits is $2000$

elementary-number-theory contest-math recreational-mathematics

answered Oct 4, 2019 at 12:24

21 votes

Accepted

Calculating Eigenvectors: Is my book wrong?

linear-algebra eigenvalues-eigenvectors

answered Nov 24, 2017 at 18:58

21 votes

Accepted

How many points uniquely define a square?

geometry

answered Jun 27 at 18:57

20 votes

Accepted

Counter-example for misused theorem in series convergence test

convergence-divergence

answered Mar 23, 2015 at 3:12

20 votes

What is the cardinality of the set of the empty set?

elementary-set-theory

answered Jan 13, 2016 at 2:22

17 votes

How many 7-note musical scales are possible within the 12-note system?

combinatorics permutations combinations music-theory

answered Jun 3, 2016 at 0:42

17 votes

Accepted

Roman Numbers - Conversion to decimal number

elementary-number-theory education number-systems decimal-expansion

answered Jun 7, 2016 at 16:01

17 votes

Why aren't these negative numbers solutions for radical equations?

algebra-precalculus radicals

answered Apr 16, 2015 at 2:04

17 votes

Accepted

What is the difference between a loop, cycle and strongly connected components in Graph Theory?

graph-theory

answered Oct 21, 2015 at 2:13

16 votes

difference between nonpositive and negative numbers?

terminology real-numbers

answered Nov 16, 2014 at 1:27

16 votes

Computing the determinant of a large matrix?

linear-algebra matrices determinant

answered Nov 9, 2017 at 0:33

16 votes

Accepted

What is special about square numbers here?

puzzle

answered Apr 13, 2019 at 22:37

15 votes

Accepted

Prove there always exists a partition such that vertices in each part have even degree

graph-theory

answered Dec 13, 2014 at 5:18

15 votes

Accepted

Why cannot $(2x^2 + x)^2$ be simplified to $2x^4 + x^2$?

algebra-precalculus

answered Jun 2, 2015 at 20:35

14 votes

Accepted

A simple mathematical expression for the periodic sequence $(1, -2, -1, 2, 1, -2, -1, 2,\dots)$

sequences-and-series complex-numbers

answered Dec 14, 2016 at 2:47

14 votes

Can infinity be divided by anything?

calculus

answered Apr 12, 2019 at 14:55

13 votes

Combination and permutation of indistinguishable objects

permutations

answered Nov 12, 2014 at 12:14

12 votes

Accepted

What came first, the $\forall$ or the $\exists$?

soft-question notation math-history

answered Mar 10, 2015 at 2:44

12 votes

Accepted

Numbers for which $n!=n^n$

elementary-number-theory inequality integers

answered Nov 8, 2015 at 17:22

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2,489 Answers

Why is $\{\{1\}\}$ not equal to $\{1,\{1\}\}$?

Why does $3^{16} \times 7^{-6}$ become $\frac{3^{16}} {7^{6}}$?

Perfect square all 9's

Can a relation be both symmetric and antisymmetric; or neither?

Weakly Connected Graphs

Expected value of the number of flips until the first head

How to compose two functions?

Is $n^7 - 77$ ever a Fibonacci number?

Two players placing coins on a round table with the goal of making the last move

What is the Scientific Notation of Zero?

Why aren't these two solutions equivalent? Combinatorics problem

Smallest number such that the sum of digits and the product of digits is $2000$

Calculating Eigenvectors: Is my book wrong?

How many points uniquely define a square?

Counter-example for misused theorem in series convergence test

What is the cardinality of the set of the empty set?

How many 7-note musical scales are possible within the 12-note system?

Roman Numbers - Conversion to decimal number

Why aren't these negative numbers solutions for radical equations?

What is the difference between a loop, cycle and strongly connected components in Graph Theory?

difference between nonpositive and negative numbers?

Computing the determinant of a large matrix?

What is special about square numbers here?

Prove there always exists a partition such that vertices in each part have even degree

Why cannot $(2x^2 + x)^2$ be simplified to $2x^4 + x^2$?

A simple mathematical expression for the periodic sequence $(1, -2, -1, 2, 1, -2, -1, 2,\dots)$

Can infinity be divided by anything?

Combination and permutation of indistinguishable objects

What came first, the $\forall$ or the $\exists$?

Numbers for which $n!=n^n$