Q: Prove that for any natural number, there exists a multiple that (in decimal form) only uses digits 0 and 1
27371
A natural number multiplied by some integer results in a number with only ones and zeros
127843
Prove that, for any natural number $k$ $\exists m \in M $ s.t i) $m$ has exactly $k$ $1$'s, an
75685
Prove that there is prime number and natural so $n\times q$ digits are $1$.
120871
VHDL interview question - detecting if a number can be divided by 5 without remainder
140155
Proving that a number with digits 1...9 in some order, ending in 5, is not a perfect square.
286
Is it true that $0.999999999\ldots=1$?
63804
Proof that every repeating decimal is rational
128415
Prove that $1<\frac{1}{1001}+\frac{1}{1002}+\frac{1}{1003}+\dots+\frac{1}{3001}<\frac43$
5978
Prove that there exists only one prime number of the form $p^2−1$ where $p≥2$ is an integer
45788
$n$-th digit in the sequence of natural numbers
10744
Prove that a number is divisible by 3 iff the sum of its digits is divisible by 3
33705
Is $0$ a natural number?
45460
Proof verification of a number theory problem involving sequences.
96846
Decimal representation begins with $N$
45456
Do the digits of $\pi$ contain every possible finite-length digit sequence?
156577
The cube of any number not a multiple of $7$, will equal one more or one less than a multiple of $7$
46561
How can I prove that all rational numbers are either terminating decimal or repeating decimal numerals?