1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

A Man gave one of his sons 10 cents and another son was given 15 cents. What time is it?
Hint: Figure out the relation between time and number, is not so easy..:)

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

What is the next number in this matchsticks series riddle?

What does below chemistry rebus means?

Find out the missing number in the picture attached:

When 99 is considered higher than 100?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?