MATHS WORKSHOP

Read And Learn

A bit of history

• The first person to devise a way of writing decimal numbers was the Dutch mathematician Simon Stevin in the 16th century. This method was not very successful.

• In the 17th century, after successive attempts, the Scottish mathematician Napier proposed the current form of notation. He separated the integer part from the decimal part using a point or a comma, and used zeros to give every figure the desired place value.

3 + 47 100 8 347 8 3|47 8 3.47

• In Spain, and in other European countries, the comma was adopted for writing decimal numbers.

• However, in the English-speaking world a point is used.

8.5 5 {∫∫∫∫∫°…∞}

This is why calculators and computers also use a point.

A number mystery

Use a calculator to check these divisions whose results are numbers with infinite decimal places:

1 : 9 = 0.111...

2 : 9 = 0.222...

3 : 9 = 0.333...

4 : 9 = 0.444...

Based on these results, 9 : 9 should be 0.99999… = 0. 9 ! .

However, we know that 9 : 9 = 1. 0.999... 5 {∫∫∫∫∫‘}

• Are these results different? Would you be able to calculate their difference?

Sharpen Your Wits

Squares

Note how the diagonal of these four squares coincides with the side of the next square.

1 2

1 2 5 4 meant 12,54

2

8 6 meant 8,06

Help

• What is the area of each one?

• How long is each diagonal?