On dividing each of 12 and 23 by a number greater than 1, we get the same remainder. What is the remainder?

The picture shows a stick just fitting into a rectangular box with dimensions 2 cm, 3 cm and 6 cm (the stick runs along the space diagonal of the box). What is the length of the stick?

A two-digit number divided by another two-digit number gives 6.25. What do we get if we multiply these two numbers?

When the length of each side of a square was reduced by 20%, its area became 16 square centimeters. What was the area of the original square?

Of three consecutive natural numbers, the square of the smallest is 308025 and the square of the next is 309136. What is the square of the largest?