CBSE Class 5 Mathematics Revision Worksheet Set 6

Topic : Factors and Multiples

(1) Test of divisibility by 8: A number is divisible by 8, if the number formed by its last 3 digits on its extreme right is divisible by 8.
For example: Let the number 279136.
The number formed by its last three digits is 136 , which is divisible by 8.
Hence 279136 is divisible by 8.

(2) Test of divisibility by 9: A number is divisible by 9, if the sum of its digits is divisible by 9.
For example: Let the number be 8316.
Sum of digits = 8+3+1+6 = 18 , which is divisible by 9.
Hence 8316 is divisible by 9.

(3) Test of divisibility by 10: A number is divisible by 10 only when its unit digit is only 0.
For example: The numbers 2560 , 17340 and 962020 has 0 as its unit digit.
Hence each one is divisible by 10.

(4) Test of divisibility by 11: A number is divisible by 11, if the difference between the sum of digits at odd places and the sum of digits at even places is either 0 or a multiple of 11.
For example: Check the number 32571 is divisible by11.
Sum of its digits at odd places = 1 + 5 + 3 = 9
Sum of its digits at even places = 7 + 2 = 9
Their difference = 9 ̶ 9 = 0
Hence given number is divisible by 11.

Prime Numbers: A number having exactly two different factors , 1 and itself is called a prime number.
For example : Prime numbers are 2 , 3 , 5 , 7 , 11 , 13 , 17 etc .

Composite Numbers: A number having more than two different factors is called a composite number.
For Example : Composite numbers are 4 , 6 , 8 , 9 , 12 , 14 etc .

Note :
• 1 is neither prime nor composite .
• The smallest prime number is 2 .
• 2 is only even prime number .

NOTE - ALL QUESTIONS ARE COMPULSORY.

(1) Which of the following numbers are divisible by 6 ?
(a) 8316
(b) 9430
(c) 7038
(d) 17703
(e) 8721

(2) Which of the following numbers are divisible by 8 ?
(a) 1372
(b) 62156
(c) 50432
(d) 59238
(e) 279136

(3) Which of the following numbers are divisible by 9 ?
(a) 7509
(b) 4186
(c) 26901
(d) 12501
(e) 3499

(4) Which of the following numbers are divisible by 10 ?
(a) 1980
(b) 1850
(c) 3206
(d) 9910
(e) 27905

(5) Which of the following numbers are divisible by 11 ?
(a) 75438
(b) 623411
(c) 20833
(d) 101011
(e) 202202

(6) Which of the following numbers are prime numbers ?
1 , 11 , 21 , 57 , 63 , 19 , 91 , 83 and 89 .

(7) Which of the following numbers are composite numbers ?
1 , 4 , 7 , 12 , 22 , 34 , 81 , 93 , 100 and 111.

(8) Write all the prime numbers between 1 and 25.

(9) Write all the prime numbers between 51 and 80.

(10) Define Prime and Composite numbers.

Please click the below link to access CBSE Class 5 Mathematics Worksheet- Revision (3)