01Computers do more than arithmetic

The word computer sounds like a machine made mainly for calculations. Calculation is important, but modern computers can do much more.

Drawing on a tablet, taking a photo, watching a video, playing a game, using a map, or guiding a robot all involve computers.

Calculate

Work through many calculations quickly

Draw

Work with colors, lines, and images

Play games

Calculate rules, movement, and graphics

Play video

Process moving pictures and sound

02Six common computer abilities

Many computer tasks can be understood as combinations of these six abilities.

Calculate

Computers can do simple arithmetic and enormous amounts of complex calculation.

Examples: scores, game physics, weather models

Process data

Text, pictures, sound, and video can be searched, sorted, changed, and transformed.

Examples: editing photos, searching text, playing music
Storage device

Store and retrieve

Computers save information for later and retrieve it when it is needed.

Examples: photos, documents, saved games

Communicate

Computers can send information to other computers and receive information back.

Examples: websites, chat, video calls

Control devices

A computer can use programs to control machines and electronic devices.

Examples: robots, cars, traffic lights

Automate tasks

Once rules are written into a program, a computer can repeat many steps automatically.

Examples: sorting data, checking items, scheduled tasks
One task often combines several abilities

In a video call, a computer captures pictures and sound, processes them, sends them through a network, receives the other person's data, and outputs the result to your screen and speakers.

03How can one computer do so many jobs?

The key is not that a computer invents its own plan. It can run different programs. A program tells the computer what information to receive, what rules to follow, and what result to produce.

The same computer
Drawing program
Game program
Music program
Your program
Different jobsDifferent programs make the computer perform different tasks.

04What are computers especially good at?

Computers are especially useful for work that would be slow or tiring for a person.

Fast

They can execute huge numbers of simple instructions quickly.

Good at repetition

They can repeat the same job again and again without getting bored.

Follow rules

When the rules are clear, they can follow a program step by step.

Handle lots of data

They can search, compare, and organize large amounts of information.

Imagine sorting 10,000 numbers from smallest to largest...
A person

Comparing them one by one would take a long time.

A computer

With a suitable algorithm and program, it can finish very quickly.

05Computers have limits too

Being powerful does not mean being able to do everything. What a computer can do depends on its programs, data, hardware, and input.

It needs instructions

Without a suitable program, it does not know how to perform the task.

It needs useful information

If the input is incomplete or wrong, the result may also be wrong.

Hardware has limits

Processing speed, memory, and storage are not unlimited.

What you now know

  • Computers do much more than arithmetic; they process text, pictures, sound, video, and other data.
  • They can calculate, process data, store information, communicate, control devices, and automate tasks.
  • The same computer can do different jobs by running different programs.
  • Computers are especially good at fast, repetitive, rule-based work involving lots of data.
  • Computers still have limits and depend on programs, data, input, and hardware.

Next question: We know what computers can do. But how do these things happen inside a computer? Next: How Do Computers Work?