EASY
IOQM - PRMO and RMO
IMPORTANT
Earn 100

Find the largest 2-digit number N which is divisible by 4, such that all integral power of N end with N.

50% studentsanswered this correctly

Important Questions on Number Theory

HARD
IOQM - PRMO and RMO
IMPORTANT
The prime numbers a, b and c are such that a+b2=4c2. Determine the sum of all possible values of a+b+c.
HARD
IOQM - PRMO and RMO
IMPORTANT
A five-digit number n=abcde¯ is such that when divided respectively by 2, 3, 4, 5, 6 the remainders are a, b, c, d, e. What is the remainder when n is divided by 100?
HARD
IOQM - PRMO and RMO
IMPORTANT
Let a, b, c be three distinct positive integers such that the sum of any two of them is a perfect square and having minimal sum a+b+c. Find this sum.
HARD
IOQM - PRMO and RMO
IMPORTANT
For a natural number n, let n' denote the number obtained by deleting zero digits, if any.  (For example, if n=260, n'=26; if n=2020, n'=22). Find the number of 3-digit numbers n for which n' is a divisor of n, different from n.
MEDIUM
IOQM - PRMO and RMO
IMPORTANT
Let the rational number pq, be closest to but not equal to 227 among all rational numbers with denominator <100. What is the value of p-3q?
EASY
IOQM - PRMO and RMO
IMPORTANT
Find the smallest positive integer n10 such that n+6 is a prime and 9n+7 is a perfect square.
HARD
IOQM - PRMO and RMO
IMPORTANT
How many ordered pairs a,b of positive integers with a<b and 100a, b1000 satisfy gcda,b:lcma,b=1:495?
HARD
IOQM - PRMO and RMO
IMPORTANT

Consider the set E of all natural numbers n such that when divided by 11,12,13, respectively, the remainders, in that order, are distinct prime numbers in an arithmetic progression. If N is the minimum number in E find the sum of digits of N.

Note: In PRMO-2019, original question was asking about maximum number in E, which couldn't be calculated. So, this was the bonus question. Only minimum value can be calculated.