Answer the riddles below, and explain how riddles help your memory

1. When a girl was six years old she hammered a nail into her favorite tree to mark her height. Five years later at age eleven, she returned to see how much higher the nail was.

If the tree grew by ten inches each year, how much higher would the nail be?

Replace the '?' by any mathematical symbol to make the expression equal to 111.

18 ? 12 ? 2 ? 3 = 111

You are on your way to visit your Grandma, who lives at the end of the valley. It's her birthday, and you want to give her the cakes you've made.

Between your house and her house, you have to cross 7 bridges, and as it goes in the land of make believe, there is a troll under every bridge.

Each troll, quite rightly, insists that you pay a troll toll. Before you can cross their bridge, you have to give them half of the cakes you are carrying, but as they are kind trolls, they each give you back a single cake. How many cakes do you have to leave home with to make sure that you arrive at Grandma's with exactly 2 cakes?