Oct 5, 2020 · Prove that some member of the sequence $7, 77, 777, 7777, \dots$ is divisible by $2019$. So far I have figured that as $2019$ is divisible by $3$, then if one of the terms of the sequence $$ …

Nov 14, 2020 · Does ⋮ mean "is divisible by" in mathematical notation? Ask Question Asked 5 years, 2 months ago Modified 2 years, 3 months ago

This is the standard way, in the specific meaning of compliance to international standards: ISO 80000-2, clause 2.7-17. Note that the vertical bar character used there is normatively identified as U+2223 …

Mar 16, 2017 · Prove that $n^2 - 1$ is divisible by $8, for every odd integer n.

Jan 1, 2018 · The totient of $210$ - the number of values between $1$ and $210$ that are relatively prime to $210$ - is $ (2-1) (3-1) (5-1) (7-1)=48$. Using this, we can say that there are …

Feb 3, 2019 · What is the probability for $abc + bc + c$ is divisible by $3$? Correct me if I'm wrong please. $abc + bc + c = c (ab + b + 1)$. We can conclude that $c$ has to be a multiple of $3$, so we …

May 28, 2017 · If you are taking $0$ as a natural number, then add 3 to the count. Since the problem asks for the numbers less than $1000$, subtract off $2$ from the count since $1000$ is divisible by …

Notice that for the numbers $1$ through $10$, inclusive, we have that $5\times 7\times 8 \times 9 = 2^3 \times 3^2 \times 5\times 7\times = 2520$ and every number $2$ to $10$ can be written as the …

Jan 27, 2022 · Find the number of eight-digit integers, composed of the digits $1,3,4,5,6,7,8,9$ such that they are divisible by $275$. For your reference I leave here some thoughts:

Same question :- Where am I overcounting? How many $3$ element subsets of the set $\ {1,2,3,...,19,20\}$ are there such that the product of the three numbers in the subset is divisible by …