Why did we reach the computer and why did the society need such a machine?

The two main answers were ‘Industrialisation’ and ‘Empire’
Firstly the empire which was the concern of the British. The British had a very strong navy. This navy kept the British interests safe and was extremely important to them. They thus needed exact and accurate locations so as not to crash into rocks and reefs. This led to the invention of ‘mobile timepieces’, however these were not very accurate.
Secondly, moving on to industrialization. The cotton mills in centers in places such as Birmingham needed calculations to help them with their engineering. Life insurance also needed calculations to make sure they did not make a loss from the dead.