Class 4 Maths – Chapter 5: Factors and Multiples. table of contents. togglefactors. properties of factors. highest common factor. least common multiple. divisibility rules:. factors. when a number is able to do divide other number completely (without leaving any remainder), then the divisor is called a factor of dividend. ex: 2x3x4x5 =120. here 2,3,4,5 are known as factors of 120 and 120 is a multiple of each 2,3,4,5. in other words we can say that each 2,3,4,5 can divide 120 completely and hence 2,3,4,5 are factors of 120. properties of factors. a. 1 is smallest factor of every number. b. every non-zero number is the largest factor of that number. c. every factor of a non-zero number is either less than or equal to given number. d. 0 is not factor of any number. highest common factor. the highest common factor (hcf) of two numbers is the largest factor that both numbers have in common. least common multiple. the least common multiple is the smallest number that is a multiple of all the numbers in a set. divisibility rules:. a- a number is divisible by 3 if sum of its digits is divisible by 3. b- a number is divisible by 9 if sum of its digits is divisible by 9. c- a number is divisible by 10 if its unit place digit is 0. d- a number is divisible by 2 if its unit place digit is 0,2,4,6,8. e- a number is divisible by 5 if its unit place digit is 0 or 5.