## Task 4 - 030624

How many matches, each $5 \mathrm{~cm}$ long, are needed to divide a square area of $1 \mathrm{~m}^{2}$ into smaller squares, each bounded by four matches?

(Two adjacent squares should only be separated by one match.)
One obtains a total of 400 squares.

In each horizontal row, there are 20 matches, so there are a total of $20 \cdot 21=420$ horizontally lying matches.

In each vertical row, there are also 20 matches, so there are a total of $20 \cdot 21=420$ vertically lying matches. Therefore, a total of 840 matches are needed.

Solutions of the II. Round 1963 taken from [5]

### 3.5 IV. Olympiad 1964

### 3.5.1 I. Round 1964, Class 6