Playing with Numbers | Chapter Assessment | English | Grade 6

If the ones digit of a number is either 0 or 5, the number is divisible by ___

• 10

• 5

• 2

• 3

Answer explanation

If the ones digit of a number is either 0 or 5, the number is divisible by 5

Tags

CCSS.3.OA.D.9

What is the least common multiple of 12 and 18 ?

• 36

• 108

• 72

• 144

Answer explanation

Option 2 is correct as common multiple of 12 and 18 are 36,72,108,144, and so lowest common multiple is 36.

Two numbers having only 1 as a common factor are called __________

• Odd numbers

• Prime numbers

• Co-prime numbers

• Even numbers

Answer explanation

Option 3 is correct because as per definition two numbers having only 1 as a common factor are called co-prime number

Tags

CCSS.4.OA.B.4

Which of the following is not a prime factor of 980 ?

• 2

• 3

• 5

• 7

Answer explanation

Option 2 is correct as prime factors of 980 are 2,5,7 hence 3 is not the prime factor of 980 Alternatively, Using Rules for divisibility we can find that 2, 5 and 7 can divide 980 but 3 can not since the sum of digits (9+8+0) = 17 is not divisible by 3.

If LCM of two numbers is 360, then which of the following can not be their HCF?

• 36

• 54

• 45

• 30

Answer explanation

The LCM of two numbers is 360. LCM of two numbers is completely divisible by the two numbers. HCF of two numbers divide the numbers completely. Hence, LCM of two numbers is always a multiple of their HCF Here, the number which can not divide 360 completely will be the answer for this question. Since 54 can not divide the number 360 completely hence it could not be the HCF of the two numbers.

Which of the following pairs is not coprime?

• 11,12

• 1,3

• 8,10

• 31,33

Answer explanation

Two numbers are coprime numbers if they have no other common factor except 1. In the given pairs of numbers, 8 and 10 have 1 as well as 2 as their common factor. So, these are not coprime numbers.

Tags

CCSS.4.OA.B.4

If the number 7254_98 is divisible by 22, the digit at _ is ?

• 1

• 2

• 6

• 0

Answer explanation

For checking the divisibility by 22, we can check if the number is divisible by 11. As 22 is the multiple of 11, if any number is divisible by 11, it will also be divisible by 22. Option 3 is correct as according to divisibility rule by 11 , if 6 is placed at _ then the number is divisible by 22, as 22 is multiple of 11 Option 1 is wrong as according to divisibility rule by 11 , if 1 is placed at _ then the number is not divisible by 22, as 22 is multiple of 11 Option 2 is wrong as according to divisibility rule by 11 , if 2 is placed at _ then the number is not divisible by 22, as 22 is multiple of 11 Option 4 is wrong as according to divisibility rule by 11 , if 0 is placed at _ then the number is not divisible by 22, as 22 is multiple of 11

Tags

CCSS.4.NBT.A.1