## What are the features of Napier bone?

A rod’s face is marked with nine squares. Each square except the top is divided into two halves by a diagonal line from the bottom left corner to the top right. The squares contain a simple multiplication table. The first holds a single digit, which Napier called the ‘single’.

**What is the importance of Napier bones?**

A means of simplifying complex calculations, they remain one of the most important advances in the study and practical application of mathematics. Napier’s ‘bones’ or ‘rods’ are just one of the methods this brilliant mathematician invented to speed up arithmetic.

### How many strips Napier’s bones?

9

Napier’s bones were invented by John Napier (1550-1617), a Scottish mathematician and scientist. They help you to do multiplication. There are 9 different ‘bones’ or strips with numbers on – see below. You may need several copies of each strip.

**Why is it called Napier’s bones?**

These slips are written on the surface of ten rods, later on called Napier’s rods (the best sets of Napier’s numbering rods were made of ivory, so that they looked like bones, which explains why they are now known as Napier’s bones).

#### How do you calculate Napier bones?

We can use Napier’s bones to multiply any two numbers. E.g. For 75 × 3, place the multiplier, the ‘7’ and the ‘5’ bone side by side (for 75) as shown below. To use the above Napier’s bones to calculate 3 × 75, sum the numbers along the slanted diagonals of the combined bones using the row applying to the multiplier.

**How does the Napier bones work?**

Napier’s bones, also called Napier’s rods, are numbered rods which can be used to perform multiplication of any number by a number 2-9. In practice, multiple sets of bones were needed for multiplication of numbers containing repeated digits.

## Who invented the Napier bones?

John Napier

Napier’s bones/Inventors

The Scot, John Napier, invented these strips (originally made from bone) about 400 years ago to help calculate multiplication and division.

**Who invented Napier rods?**

### How does Napier bone work?

By placing “bones” corresponding to the multiplier on the left side and the bones corresponding to the digits of the multiplicand next to it to the right, and product can be read off simply by adding pairs of numbers (with appropriate carries as needed) in the row determined by the multiplier.

**Who and when Napier bone was invented?**

John Napier, the inventor of logarithms, also invented this aid to calculation known as ‘Napier’s Bones’ in 1617. The ‘bones’ consist of a set of rectangular rods, each marked with a counting number at the top, and the multiples of that number down their lengths.

#### Who invented calculator?

Texas Instruments

Jack KilbyEdith Clarke

Calculator/Inventors