Unit 1
Bits and data.
Bits and bytes, counting in base 2 and base 16, and how a computer stores colour, pictures and text as numbers.
Before this unit
- Numbers Mathematics
The unit, lesson by lesson
Lessons
4 lessons · 24 practice questions · about 2 hours
Bits on switches
A switch that is a number: what a bit is, how many patterns two bits make, place value in base 2, and why 10 in base 2 is two.
Counting in base 2
How many values fit in so many bits, why each bit doubles them, the byte and 255, and converting between base 2 and base ten both ways.
Colour and hexadecimal
A pixel is three numbers: how many colours so many levels give, bits per pixel, counting in base 16, web colour codes, and light that adds up.
Images and text as numbers
The size of a picture: resolution, colour depth and bytes, and why doubling the width makes the file four times bigger; and text as numbers, from ASCII to Hebrew letters in UTF-8.