Class 7 - Chapter 1: Number System

 Chapter 1: Number System

A. Fill in the blanks.

1. 2

2. Decimal 

3. 8

4. Binary

5. Hexadecimal

B. State True or False. 

1. False

2. True 

3. True 

4. True 

5. False

C. Select the correct option. 

1. a. Binary

2. a. 1

3. a. 10-16 

4. b. 1

5. a. 2

D. Answer the following questions.

1. A number system is a way of expressing numbers using digits or symbols. Different types of number systems include Decimal Number System, Binary Number System, Octal Number System, and Hexadecimal Number System

2. The steps to convert a decimal number to a binary number: ● Divide the decimal number by 2.

● Record the quotient below the number and the remainder to the right. 

● Repeat the previous step until the quotient becomes zero.

● The binary equivalent is obtained by reading the remainders in reverse order.

3. LSD (Least Significant Digit) is the rightmost digit in a number. For example, in the number 456, 6 is the LSD. Whereas MSD (Most Significant Digit) is the leftmost digit in a number. In the number 456, 4 is the MSD.

4. A computer understands binary number system. It consists of only two digits, i.e., 0 and 1. The data that is entered into a computer is converted into its binary equivalent.

5. The hexadecimal number system consists of 16 digits: 0-9 and the letters A-F, where A-F represents digits 10 to 15 with the base 16. This number system is also known as Hex, where Hex=6 and Decimal = 10, so it is called the Hexadecimal.

My Activity on Number System (Page 15) 

A. Convert the following:

a. (68)10 = (1000100)2

b. (987)10 = (1111011011)2 

c. (10101)2 = (21)10

B. Perform binary addition on the following: 

a. 10101+00111=110000

b. 11001101+1000101101=1101111010 

c. 1101+1001=10110

C. Find the difference between the following binary numbers: 

a. 10011−01010=101

b. 11001001−01100110=1010111 

c. 111−001=110