Question

What will be the difference between the largest and smallest four digit number made by using distinct single digit prime numbers?

Answer 1

difference between largest and smallest 4 digit no is 8999

Answer 2

Ans. The number of numbers which are divisible by 1 and itself only =25

Also, the number of numbers which are divisible by at least one more number except 1 and itself(i.e., composite numbers) 99-25=74

So, required difference =74-25=49

So---- 49 will be the answer