Reading 101 in binary: digits, not a hundred and one
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. How should you say the binary number 101 (written 101₂) out loud?
2. What does the small 2 in 101₂ tell you?
3. What is the value of 101₂ in decimal?
4. The binary number 10₂ is worth:
5. You see the number 11 with no small 2 next to it in a maths class. Which is the safer assumption?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1101_2 | A10 in binary is two, not ten. The digits one and zero show 1 two and 0 ones, so 10_2 = 2. | |
| 210_2 | BA binary number written with a base subscript 2. Say it 'one zero one'. It equals 5 in decimal. | |
| 3Write the number 101 so people know it is binary, not one hundred and one | CThe binary number 'one zero', which equals 2 in decimal, not ten. | |
| 4Write the number 101 so people know it is decimal, meaning one hundred and one | DBinary numbers are not read as hundreds. The 2 subscript means base 2, so say 'one zero one' and its value is five. | |
| 5Reading 101_2 aloud as 'one hundred and one' | E101_2 | |
| 610_2 = 10 | F101_10 |
C
Definitions
101_2
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
Binary five is written 101 in base _
2.
Say 101 base 2 digit by _____: one zero one
3.
10 in base 2 is _ in decimal, not ten
4.
101 base 2 = _ + 0 + 1 = 5
5.
101 in base __ is one hundred and one
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
101_2 is a decimal number
B
Say it: one zero one
C
Its decimal value is 5
Question 2
A
binary ← 101_2
B
Read digit by digit: 1, 0, 1
C
decimal ← 101
Question 3
A
x ← 10_2
B
Say it: ten
C
x in decimal is 2
Question 4
A
Write 101 in base 2 as 101_10
B
The small 2 is the base
C
It means binary
Question 5
A
bits ← 1 1 0
B
Say it: one hundred and ten
C
110_2 is six in decimal
Answer Key
Reading 101 in binary: digits, not a hundred and one
Section A: Quick Questions
Q1
A — One zero one
Q2
B — The number is written in base 2 (binary)
Q3
A — 5
Q4
B — Two
Q5
A — It is decimal, so it is eleven
Section B: Match the Pairs
Q1
101_2 → A binary number written with a base subscript 2. Say it 'one zero one'. It equals 5 in decimal.
Q2
10_2 → The binary number 'one zero', which equals 2 in decimal, not ten.
Q3
Write the number 101 so people know it is binary, not one hundred and one → 101_2
Q4
Write the number 101 so people know it is decimal, meaning one hundred and one → 101_10
Q5
Reading 101_2 aloud as 'one hundred and one' → Binary numbers are not read as hundreds. The 2 subscript means base 2, so say 'one zero one' and its value is five.
Q6
10_2 = 10 → 10 in binary is two, not ten. The digits one and zero show 1 two and 0 ones, so 10_2 = 2.
Section C: Definitions
Q1
101_2 — A small 2 after a number shows it is binary (base 2). Say it digit by digit: one zero one. It means five in decimal, not one hundred and one.Section D: Fill in the Blanks
Q1
Binary five is written 101 in base 2Q2
Say 101 base 2 digit by digit: one zero oneQ3
10 in base 2 is 2 in decimal, not tenQ4
101 base 2 = 4 + 0 + 1 = 5Q5
101 in base 10 is one hundred and oneSection E: Spot the Error
Q1
A — The small 2 after the number means base 2, so 101_2 is a binary number, not a decimal one. The line should read: 101_2 is a binary number.
Q2
C — 101_2 is read as digits and is worth five in decimal, not one hundred and one. The line should be: decimal ← 5.
Q3
B — Binary numbers are said digit by digit, so 10_2 is said 'one zero', not 'ten'. It is worth two in decimal. The line should be: Say it: one zero.
Q4
A — The small number after the digits is the base. Base 2 needs a small 2, so it should be 101_2, not 101_10.
Q5
B — Binary digits are read one at a time, so 110_2 is said 'one one zero'. It is not 'one hundred and ten'. The line should be: Say it: one one zero.