HARD
Earn 100

Find the LCM by both listing and common division methods.

42, 56, 70

Important Questions on Playing with Numbers

HARD
Suppose a,b,c are positive integers such that 2a+4b+8c=328. Then a+2b+3cabc is equal to-
EASY

What is the LCM of x3+8, x2+5x+6 and x3+4x2+4x ?

HARD
The number of 6-digit numbers of the form ababab (in base 10) each of which is a product of exactly 6 distinct primes is
MEDIUM

What is the number of Prime factor in 1518×410×69.

EASY
The least number which is exactly divisible by 5, 6, 810 and 12 is:
EASY
Which of the following number is an odd and prime number?
EASY
If a and b are positive integers such that a2-b2 is a prime number, then
EASY

The sum of all the factors of 156 is: 
(A) 392
(B) 235
(C) 390
(D) 379

HARD
How many ordered pairs a,b of positive integers with a<b and 100a, b1000 satisfy gcda,b:lcma,b=1:495?
MEDIUM
What is the largest two-digit number which when divided by 6 and 7 gives the remainder 3 and 4 respectively?
EASY
How many two digit numbers are divisible by 9
MEDIUM
Find the LCM of 257, 1528, 2021,
EASY
The sum of the squares of the digits of the largest two-digit prime number is:
MEDIUM
For an integer n, let Sn=n+1,n+2,., n+18. Which of the following is true for all n10 ?
EASY

The total number of factors of 1156 is: 

(A) 9 

(B) 8 

(C) 10 

(D) 11 

EASY
Which of the following is not a pair of prime numbers ?
EASY

The prime factorisation of 240 is:

(A) 23×32×5 

(B) 24×32×5

(C) 24×3×5

(D) 25×3×5

 

EASY
How many numbers from 1 to 1000 are divisible by 23,4 and 5?
EASY
The least number which is exactly divisible by 4, 5, 8, 10, and 12 is _____.
EASY
If x is a prime number, LCM of x and its successive number would be: