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

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?

The more it dries, the wetter it becomes. Can you tell what it is?

If a boy blows 18 bubbles,
Then pops 6 eats 7 and then
He pops 5 and blows 1.
How many are left?

I can be cracked, made, told, and played. What am I?

Sally lives in a place where six months of the year is mild summer and the temperature drops significantly the other six months. She owns a lake where there is a small island. She wants to build a house on the island and needs to get materials there. She doesn’t have a boat, plane, or anything to transport them to the island. How does Sally solve this problem?

Can you find the hidden animal in the picture below?

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?