How many prime numbers are there below 30?

How many odd numbers are there below 25.

In a certain city, all telephone numbers have six digits How many telephone numbers are there with distinct digits?

. How many numbers are there in the 30^(th) row of this number pyramid?

How many 4 digit numbers are there with no digit repeated?

Consider the arithmetic sequence -74,-68,-62,…….. How many negative numbers are there in this sequence? - Find the first positive. number in this sequence.

How many three-digit numbers are there, which leave a remainder 3 on division by 7 ?

In a certain city, all telephone numbers have six digits If repetition of digits is possible, how many telephone numbers are there in the city.

Consider 3 digit numbers which are multiple of 6. How many numbers are there of this type ?

How many number of moles are there in 1 g of Ca

See the pictures below: How many small squares are there in each rectangle? Continuing this pattern, is each such sequence of numbers, an arithmetic sequence?