How do you go from 98 to 720 using just one letter?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

Can you find the missing number in the third row?
35 20 14
27 12 18
5 2 ?

All of Jacob's shoes are red except two.
All of Jacob's shoes are green except two.
All of Jacob's shoes are yellow except two.

How many shoes does Jacob have?

Arrange the numbers 1, 2, 3, 4, 5, 6, 7, 8 and 9 above and below the division line in a manner that the thus formed fractions equal to 1/3.

(You can use one number only once)

There is a box. The area of its top is 240 square units, the area of the front is 300 square units and the area of the end is 180 square units.

Can you calculate the dimensions of this box with the given data?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

Our product and our sum always give the same answer. Who are we?

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube?