Practice30Create account

Kabir circled all the prime numbers from 51 to 90 in the grid. Exactly one of his circled numbers is NOT prime. Which one?

Class 6Prime and Composite NumbersPlaying with Numbers
  • A89
  • B87
  • C83
  • D53

Step-by-Step Solution

(its digit sum 15 is a multiple of 3), so 87 is composite. 53, 83 and 89 have no factor other than 1 and themselves.
Answer: B) 87

Master this chapter in 30 minutes a day.

Don't just memorise the answer — build a daily practice habit.

Practice 5 Similar Questions Free →

All Prime and Composite Numbers practice questions

More Class 6 Prime and Composite Numbers practice

Arjun uses all 12 counters to make rectangles (3 rows of 4 and 4 rows of 3 count as the…Each child laid out their counters in a single row, as shown. Whose counters can NOT be…Twin primes are pairs of primes that differ by 2, like 11 and 13. How many pairs of twin…Farhan has started this factor tree for 72. When every branch ends in a prime, how many…Ravi says, "Every prime number is odd." Which card proves him wrong?