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CTET 7 Feb 2026 Paper 1, Question 34

Topic: Numbers

Q34

What is the difference between the greatest 4-digit number and the least 4-digit number formed by using the digits 1, 5, 0 and 7 once?

  1. (1) 6093
  2. (2) 6003
  3. (3) 6453Correct answer
  4. (4) 6531

Solution.

CBSE answer: (3)

Answer: (3) 6453

  1. Greatest number: digits in decreasing order, 7510.
  2. Least 4-digit number: 0 cannot be first, so put 1 first, then 0, 5, 7: 1057.
  3. Difference: 7510−1057=64537510 - 1057 = 6453.

Trap: taking 0157 as the least number is wrong, because it is only a 3-digit number.