[ Arithmetic. Mental arithmetic, etc. ] $[$ Word problems (other). ]

Snow White cut out a large square from batiste and put it in a chest. The First Dwarf came, took out the square, cut it into four squares, and put all four back into the chest. Then the Second Dwarf came, took out one of the squares, cut it into four squares, and put all four back into the chest. Then the Third Dwarf came, and he took out one of the squares, cut it into four squares, and put all four back into the chest. The same thing was done by all the other dwarfs. How many squares were in the chest after the Seventh Dwarf left?
How many squares does each dwarf "add"?

## Solution

Each dwarf takes 1 square from the chest and puts in 4 - that is, adds 3 squares. Therefore, after the

Seventh Dwarf leaves, there will be $1+3 \cdot 7=22$ squares in the chest.

## Answer

22 squares.