New posts in arithmetic

Why worry about commutativity but not associativity in The Fundamental Theorem of Arithmetic?

elementary-number-theory arithmetic associativity

Mathematics behind this card trick

modular-arithmetic arithmetic card-games

What is this operator called?

elementary-number-theory terminology arithmetic tetration

$-3^2 = 9?\ $ Correct syntax for a negative number with an exponent.

notation arithmetic exponentiation

Why is $\frac{1}{\frac{1}{X}}=X$?

arithmetic intuition inverse fractions

Largest multiple of $7$ lower than some $78$-digit number?

elementary-number-theory modular-arithmetic arithmetic

The proof of $\sqrt{2}$ is not rational number via fundamental theorem of arithmetic.

Prove that $\sqrt{7}^{\sqrt{8}}>\sqrt{8}^{\sqrt{7}}$

inequality arithmetic exponentiation number-comparison

Prove: if $n\mid 7^n+6^n$ and $n>1$, then $13\mid n$

elementary-number-theory modular-arithmetic arithmetic

Why does this age calculation trick work?

arithmetic puzzle calendar-computations

What is the answer to this infamous "Common Core" question?

arithmetic word-problem

What would Gauss do in this case: adding $1+\frac12+\frac13+\frac14+ \dots +\frac1{100}$?

elementary-number-theory arithmetic harmonic-numbers

Is (a/b)/c equal to a/(b*c) for integer division?

elementary-number-theory arithmetic integers programming

How did the rule of addition come to be and why does it give the correct answer when compared empirically?

How to define addition through multiplication?

number-theory arithmetic

Rules for rounding (positive and negative numbers)

Is $1+1 = 2$ true in any base?

elementary-number-theory arithmetic number-systems

Rules of thumb for divisibility

elementary-number-theory arithmetic divisibility

Trick with 3-digit numbers, always get 1089

algebra-precalculus arithmetic

a big number that is obviously prime?

prime-numbers arithmetic recreational-mathematics mental-arithmetic