Explaining how digital systems use numbers for data
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. Which sentence explains how a computer stores a picture?
2. Which digits does binary use?
3. How do we link binary to a light switch?
4. A black-and-white pixel grid is stored using 0s and 1s. What could the 0 and 1 stand for?
5. Which sentence about data types is true?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1A computer stores a picture as numbers | AA computer does not keep a picture as a photo. It turns the picture into numbers, for example pixel values in a grid. | |
| 2Binary uses only 0 and 1 | BDigital systems turn pictures into numbers, such as a grid of pixels where each pixel has a number. | |
| 3A small pixel grid can store a black-and-white picture, where 0 is a white pixel and 1 is a black pixel. | CBinary has two digits, which match off (0) and on (1) like a light switch. | |
| 4The data type decides what you can do with a value: numbers can be added, but text is joined together. | DBinary only has two digits, 0 and 1. The digit 2 is not used in binary. | |
| 5Binary uses the digits 0, 1 and 2. | E5 + 5 = 10 and "5" + "5" = "55" | |
| 6A computer keeps a picture as a photo inside, not as numbers. | F0 1 1 0 |
C
Definitions
A computer stores a picture as numbers
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
A computer stores a picture as _______.
2.
Binary uses only 0 and _.
3.
In binary, 1 means on and 0 means ___.
4.
A picture is a grid of tiny ______.
5.
The _________ decides what you can do
with a value.
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
row = [0, 1, 2, 0]
B
for pixel in row:
C
if pixel == 1:
D
print('black')
Question 2
A
bit = 1
B
state = 'off'
C
if bit = 1:
D
state = 'on'
Question 3
A
colours = ['white', 'black']
B
pixel = 2
C
print(colours[pixel])
Question 4
A
age = 10
B
name = 'Sam'
C
print(age + 5)
D
print(name - '!')
Question 5
A
is_on = True
B
bit = 0 if is_on else 1
C
print(bit)
Answer Key
Explaining how digital systems use numbers for data
Section A: Quick Questions
Q1
A — A computer stores a picture as numbers, one for each pixel in the grid.
Q2
A — Only 0 and 1
Q3
B — 0 is like off and 1 is like on
Q4
A — 0 is a white pixel and 1 is a black pixel
Q5
B — The data type decides what you can do with a value.
Section B: Match the Pairs
Q1
A computer stores a picture as numbers → Digital systems turn pictures into numbers, such as a grid of pixels where each pixel has a number.
Q2
Binary uses only 0 and 1 → Binary has two digits, which match off (0) and on (1) like a light switch.
Q3
A small pixel grid can store a black-and-white picture, where 0 is a white pixel and 1 is a black pixel. → 0 1 1 0
Q4
The data type decides what you can do with a value: numbers can be added, but text is joined together. → 5 + 5 = 10 and "5" + "5" = "55"
Q5
Binary uses the digits 0, 1 and 2. → Binary only has two digits, 0 and 1. The digit 2 is not used in binary.
Q6
A computer keeps a picture as a photo inside, not as numbers. → A computer does not keep a picture as a photo. It turns the picture into numbers, for example pixel values in a grid.
Section C: Definitions
Q1
A computer stores a picture as numbers — Digital systems turn pictures, colours and text into numbers. Binary uses only 0 and 1, like off and on, and the data type decides what you can do with it.Section D: Fill in the Blanks
Q1
A computer stores a picture as numbers.Q2
Binary uses only 0 and 1.Q3
In binary, 1 means on and 0 means off.Q4
A picture is a grid of tiny pixels.Q5
The data type decides what you can do
with a value.Section E: Spot the Error
Q1
A — A black-and-white pixel row uses binary, which has only the digits 0 and 1. The 2 is not a binary digit. It should be row = [0, 1, 1, 0].
Q2
C — A single = stores a value. To compare the bit with 1 you need the double equals ==. It should be if bit == 1:.
Q3
B — One bit can only be 0 or 1, so it picks one of two colours. The number 2 does not match any colour in the list. It should be pixel = 0 or pixel = 1.
Q4
D — Text (a string) can be joined with + but cannot be subtracted. The data type decides what you can do. It should be print(name + '!').
Q5
B — Binary links on and off to 1 and 0. On should be 1 and off should be 0, but this line swaps them. It should be bit = 1 if is_on else 0.