Free Factors and Multiples 02 Practice Test - 4th Grade
Question 1
The least number which is exactly divisible by 6, 12, 24 is ___.
SOLUTION
Solution : A
The least number which is exactly divisible by 6, 12, 24 is the LCM of the 3 numbers.
26,12,2423,6,1223,3,633,3,31,1,1
LCM of 6, 12 and 24
=2×2×2×3=24
Question 2
The number 7 has ___ multiples.
SOLUTION
Solution : D
To get multiples of any number, we multiply counting numbers with that number.
Since there are infinite counting numbers, multiples of any number are also infinite.
Question 3
The LCM of 3 and 5 is:
SOLUTION
Solution : B
Factors of 3: 1, 3
Factors of 5: 1, 5
3 and 5 are co-prime numbers because 1 is their only common factor.
LCM of co-prime numbers is equal to the product of the numbers.
So,
LCM of 3 , 5=3×5=15
Question 4
The HCF of 13 & 7 is
SOLUTION
Solution : C
Factors of 13: 1, 13
Factors of 7: 1, 7
The only common factor is 1.
Hence the HCF of 13 and 17 is 1.
Question 5
Find the greatest number that divides 2, 3 & 6 exactly.
SOLUTION
Solution : B
The greatest number that can divide 2, 3 and 6 exactly is their HCF.
Factors of 2: 1, and 2
Factors of 3: 1, and 3
Factors of 6: 1, 2, 3, and 6
So, the common factor is 1 which is also the HCF.
Question 6
How many common factors do 6 and 4 have?
SOLUTION
Solution : A
Factors of 6: 1, 2, 3, 6
Factors of 4: 1, 2, 4
Common factors : 1 ,2
Hence, 6 and 4 have 2 common factors.
Question 7
Three measuring rods are 6 cm, 4 cm and 8 cm long. Find the shortest length that can be measured exactly by each one of these rods.
SOLUTION
Solution : B
To find the shortest length that can be measured exactly by using each one of these rods, we need to find the LCM of their lengths.
26,4,823,2,423,1,233,1,11,1,1
LCM =2×2×2×3=24 cm
Therefore, 24 cm is the shortest length that can be measured exactly by each one of these rods.
Question 8
The largest factor of a number is ___
SOLUTION
Solution : A
The largest factor of a number is the "number itself".
For example, the highest factor of 48 is 48.
The lowest factor of any number is 1.
Question 9
Except
SOLUTION
Solution :1 is an unique number. It is neither a prime number nor a composite number.
1 is the only number that does not have two factors.
Question 10
Find the LCM of 25, 50 and 100.
SOLUTION
Solution : D
Using the prime factorization method:
225,50,100525,25,5055,5,1021,1,21,1,1
LCM of 25, 50 and 100 =2×5×5×2=100