ASCII and its bits per character

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Quick Questions

Shade in the A or B circle for each question.

1. How many bits does standard ASCII use for each character's code?

A 7 bits

B 16 bits

2. How many different characters can standard 7-bit ASCII represent?

A 128

B 256

3. What does ASCII stand for?

A Advanced System Code for Internet Interaction

B American Standard Code for Information Interchange

4. Extended ASCII uses 8 bits per character. How many characters can it represent?

A 256 characters

B 512 characters

5. Which set of characters does ASCII cover?

A Letters from every world language and emoji

B English letters, digits and punctuation

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
12^7 = 128		AStandard ASCII uses 7 bits for 128 characters. 8 bits would give 256, which is extended ASCII.
22^8 = 256		BThe number of characters that extended ASCII (8 bits) can represent
3Standard ASCII gives every character a 7-bit code, but it is usually stored in 8 bits with a leading 0		CASCII stands for American Standard Code for Information Interchange.
4ASCII covers only English letters, digits and punctuation, so it cannot hold characters from other languages		DA = 01000001
5Standard ASCII uses 8 bits to give 128 characters		EASCII: A b 7 ! ? (no Chinese characters)
6ASCII stands for All Standard Character Information Index		FThe number of characters that standard 7-bit ASCII can represent

Definitions

ASCII

Fill in the Blanks

Complete each line of code by filling in the missing parts.

American Standard Code for Information Interchange = _____

Original ASCII uses _ bits per character

7 bits give 2^7 = ___ different codes

Extended ASCII: _ bits = 256 characters

ASCII covers only _______ letters, digits, and punctuation

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A bits = 7

B chars = 2 * bits

C print(chars)

Question 2

A char = 'A'

B code = chr(char)

C print(code) # 65

Question 3

A word = 'HELLO'

B bits = 8

C n = len(word)

D total = n + bits

Question 4

A ascii_chars = 2 ** 8

B extended_chars = 2 ** 8

C print(ascii_chars)

Question 5

A bits = 8

B values = 2 ** bits

C print('Extended:', bits)

Answer Key

ASCII and its bits per character

Section A: Quick Questions

A — 7 bits

A — 128

B — American Standard Code for Information Interchange

A — 256 characters

B — English letters, digits and punctuation

Section B: Match the Pairs

2^7 = 128 → The number of characters that standard 7-bit ASCII can represent

2^8 = 256 → The number of characters that extended ASCII (8 bits) can represent

Standard ASCII gives every character a 7-bit code, but it is usually stored in 8 bits with a leading 0 → A = 01000001

ASCII covers only English letters, digits and punctuation, so it cannot hold characters from other languages → ASCII: A b 7 ! ? (no Chinese characters)

Standard ASCII uses 8 bits to give 128 characters → Standard ASCII uses 7 bits for 128 characters. 8 bits would give 256, which is extended ASCII.

ASCII stands for All Standard Character Information Index → ASCII stands for American Standard Code for Information Interchange.

Section C: Definitions

ASCII — A character set that gives each character a 7-bit code (128 characters), usually stored in 8 bits. Extended ASCII uses 8 bits for 256 characters.

Section D: Fill in the Blanks

American Standard Code for
Information Interchange = ASCII

Original ASCII uses 7 bits per character

7 bits give 2^7 = 128 different codes

Extended ASCII: 8 bits = 256 characters

ASCII covers only English letters, digits,
and punctuation

Section E: Spot the Error

B — The number of different codes is 2 to the power of the bits, so it must be 2 ** bits. 2 ** 7 = 128 characters. 2 * bits gives 14, which is wrong.

B — To get the ASCII number for a character you use ord(). chr() goes the other way (number to character) and would cause an error here. It should be code = ord(char).

D — Each character is stored in 8 bits, so the total is the number of characters multiplied by the bits per character: n * bits (5 x 8 = 40 bits), not added.

A — Standard ASCII uses 7 bits, giving 2 ** 7 = 128 characters. 2 ** 8 = 256 is the size of extended ASCII, which has its own variable on the next line.

C — The label says how many characters extended ASCII holds, which is stored in values (256). Printing bits would only show 8. It should print values.