CodeHS CSP Digital Information Unit

Which of these values can be stored in a single bit?

• light switch

• current temperature

• 4 directions (i.e. north, south, east & west)

• months of the year

Answer explanation

A single bit can represent two states, such as on/off or true/false. A light switch fits this definition, as it can be either on (1) or off (0). The other options require more than one bit to represent multiple values.

The Apple iPhone includes a settings menu where you can toggle various accessibility options on or off: (See image to the left)

What is the minimum number of bits that can represent those options?

Answer explanation

Each option has an on or off, so each option requires 1 bit. 3 options each needing 1 bit. Therefore 3 bits are needed.

Which of the below are binary digits?

• A binary digit is 1 of ten values (0-9)

• A binary digit is 1 of two values (0-1)

• A binary digit is ten values of (0-9).

• A binary digit is two values of (0-1)

Answer explanation

A binary digit, or bit, represents one of two values: 0 or 1. Therefore, the correct choice is 'A binary digit is 1 of two values (0-1)', as it accurately defines the concept of binary digits.

If I have 4 bits how many different numbers may I represent?

• 2

• 4

• 8

• 16

Answer explanation

With 4 bits, you can represent 2^4 different combinations. This equals 16, as each bit can be either 0 or 1, leading to 16 unique numbers from 0000 to 1111 in binary.

Which of the following is a single byte of digital information?

Each choice is expressed in binary.

• 1

• 1001100101001

• 01011010

• 1001

Answer explanation

A single byte consists of 8 bits. The correct choice, 01011010, is 8 bits long. The other options either have fewer bits (1 and 1001) or more bits (1001100101001), making them not a single byte.

Your programmer friend told you that they just turned 11110 years old, in binary.

How old are they in decimal?

Answer explanation

11110

2⁴ * 1 + 2³ * 1 + 2² * 1 + 2¹ * 1 + 2⁰ * 0 = 16 + 8 + 4 + 2 + 0 = 30

Your classmate constructs a simple computer that adds numbers. There are 5 wires for inputting the first number, and the wires are currently "on", "on", "off, "on", "off", or 11010 binary.

What decimal number does that represent?

Answer explanation

11010

2⁴ * 1 + 2³ * 1 + 2² * 0 + 2¹ * 1 + 2⁰ * 1 = 16 + 8 + 2 = 26

You're visiting a Computer Science building at a college, and they've decided it'd be fun to display all the room numbers in binary. You're going to room 13.

What binary number should you look for on the door of room 13?

Type the binary number without any spaces:

Answer explanation

13 = 2³ + 2² + 2⁰

¹¹⁰¹

You've decided to use binary to communicate "secret" messages to your friend, and you want to tell them to meet you at locker 44.

What would be the binary representation of the decimal number 44?

Type the binary number without any spaces:

Answer explanation

44 = 2⁵ + 2³ + 2²

101100

Which of these lists correctly orders the binary numbers from smallest to largest?

• 
• 
• 
• 

Answer explanation

00010001 = 17

00010101 = 21

00100111 = 39

01001000 = 72