Ada Lovelace 
1815–1852 

Born Augusta Ada Byron, 
the daughter of the poet 
Lord Byron, Ada Lovelace 
was given a mathematical 
education on the insistence 
of her mother. Lovelace 
worked with Charles Babbage translating and 
annotating works of an Italian engineer. It was 
through her extensive notes on the translation that 
she wrote what is considered to be the first computer 
program: an algorithm to be used on a machine!

Charles Babbage 
1791–1871

A mathematician and 
prolific inventor, Babbage 
is often considered to be 
the father of computing 
for his work on the first 
mechanical computer. 
Babbage’s machine carried out calculations 
using levers and gears rather than the 
electrical circuits of today. It had many 
technical components, including a unit that 
allowed for loops and memory leading to 
the modern computers we have today. 

Babbage built two machines: 
The Difference Engine and 
The Analytical Engine

If The Difference Engine had 
been completed, it would 
have weighed over 15 tonnes 

Data and programs were 
provided to the Analytical 
Engine by punch cards 
which represented data.

The programming 
language used by Lovelace 
was similar to modern 
assembly languages 

Lovelace was one of the 
first to suggest a computer 
might act on something 
other than numbers

At each increase of knowledge, 
as well as on the contrivance of 
every new tool, human labour 
becomes abridged (shortened). 

Charles Babbage

Fast facts

[The Analytical Engine] 
might act upon other things 
besides numbers...

Ada Lovelace

First computer designer First computer programmer

Charles Babbage and Ada Lovelace

ICT Innovators 



How do Difference Engines Work? 

Take the equation Y = 2X+2

When the X wheel is at 1 the final wheel gives a Y value of 4.

Trace what would happen if the X wheel is turned one turn.

One of the first ever computers was known as a Difference Engine. This mechanical device would spin wheels 
with numbers attached. Each wheel would then turn the wheel next to it based on the connection of gears 
between each wheel.

These Difference Engines could be used to do large amounts of mathematical calculations such as 
trigonometry and quadratic equations.

Activity 1 – Broken Difference Engine

Table of results 
created by this 
engine

Broken Difference Engine

In each of the engines below there is a wheel that is incorrectly labelled. 

Use the table of results created by each engine to identify the mislabelled wheel (A or B).

Algorithmic Thinking

Can you work backwards from the table to come up 
with a difference engine for these results?

ICT Innovators 



Activity 2 – Broken Difference Engine

One of the first ever computers was known as a Difference Engine. This mechanical device would spin wheels 
with numbers attached. Each wheel would then turn the wheel next to it based on the connection of gears 
between each wheel.

These Difference Engines could be used to do large amounts of mathematical calculations such as 
trigonometry and quadraticequations.

How do Difference Engines Work? 

Take the equation Y = 2X+2 
When the X wheel is at 1 the final wheel gives a Y value of 4.
Trace what would happen if the X wheel is turned one turn.

Y4

Table of resultscreated by this 
engine

Broken Difference Engines

864216141210321076248102X56+2414012X
The difference engines below are missing one or more of the following wheels. 

XY02142638

7705216032454X121049252169X2364641022402834+4164206183624306X1214026128102X4
Can you figure out which wheel belongs where?

Y= + 5Y= + 


XY051729311

0X5+507919171513112134567
5
Y

0X
Y

XY0015212321

0
Algorithmic Thinking

Can you work backwards from the table to come up 

X

with a difference engine for these results?

XY04110216322
Images: Vectors from www.freepik.com