Write the smallest and the biggest two digit prime number.

Write the smallest and the biggest three digit composite number.

The sum of any three odd natural numbers is odd. Justify this statement with an example.

The digits of the prime number 13 can be reversed to get another prime number 31. Find if any such pairs exist upto 100.

Find the HCF and the LCM of the numbers 154, 198 and 286.

What is the greatest possible volume of a vessel that can be used to measure exactly the volume of milk in cans (in full capacity) of 80 litres, 100 litres and 120 litres?

The traffic lights at three different road junctions change after every 40 seconds, 60 seconds and 72 seconds respectively. If they changed simultaneously together at 8 a.m at the junctions, at what time will they simultaneously change together again?

Find the sum of all the prime numbers between 10 and 20 and check whether that sum is divisible by all the single digit numbers.

Find the smallest number which is exactly divisible by all the numbers from 1 to 9.

In an apartment consisting of 108 floors, two lifts A & B starting from the ground floor, stop at every 3^rd and 5^th floors respectively. On which floors, will both of them stop together?