How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

I am a number I am not an odd number I am higher than 90 I am not higher than 100 If you subtract me from 100, you get nothing. What number am I?

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

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

Solve the mathematical equation in the picture below.

Solve below popular number sequence
314 159 265 358 979 323 846 ?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.
How many remain now?

There once were seven dwarfs who were all brothers. They were all born two years apart. The youngest dwarf is seven years old. How old is his oldest brother?

John can fit six large chocolate boxes or nine small chocolate boxes into a carton. How many cartons will he require to put sixty-six chocolate boxes into?