I am six years old, my brother is eleven, and my sister is eight years older than my brother. So how old is my sister?
She is nineteen
There are forty-two trees in the forest, how many trees are there left if you cut down eighteen?
Twenty-four trees.
You have fifteen doughnuts, your mother ate one, your sister ate three, and your grandpa ate four. How many doughnuts you have left?
Seven dougnuts.