Test:Factors & Mulitples - 2 - CTET & State TET MCQ

20 expressed as a product of primes is 2 × 2 × 5.

The sum of the first five multiples of 8 is 8 + 16 + 24 + 32 + 40 = 120.

Factors of 9 = 1, 3, 9
Factors of 36 = 1, 3, 4, 6, 9, 12, 36
Common factors are 1, 3, 9.

The prime numbers between 50 and 100 are 53, 59, 61, 67, 71, 73, 79, 83, 89 and 97, which are 10 in number.

Co-prime numbers are numbers that have no common factor other than 1.

5 and 25 are factors of 125.
Hence, only two numbers are factors of 125 from the given list.

• A. 6 is a multiple of 18: This is false. A multiple of 18 would be a number like 18, 36, 54, etc. 6 is not a multiple of 18.

• B. 24 is a multiple of 3: This is true. 24 is divisible by 3 (24 ÷ 3 = 8), so 24 is a multiple of 3.

• C. 5 is a factor of 20: This is true. 20 is divisible by 5 (20 ÷ 5 = 4), so 5 is a factor of 20.

• D. 88 is a factor of 4: This is false. A factor of 4 would be a number that divides 4 exactly. However, 88 is much larger and does not divide into 4.

Correct evaluation:

A. False
B. True
C. True
D. False

Thus, the correct option is:

False, True, True, False.

23 × 7 = 161.

H.C.F. of 11, 33 and 88 is 11.
L.C.M. of 11,33 and 88 is 11 × 3 × 8 = 11 × 24 = H.C.F .× 24.

Multiples of 7: 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91.......
Multiples of 12: 12, 24, 36, 48, 60, 72, 84, 96.....
Smallest number is 84 because 84 is minimum common multiple of 7 and 12.

Option 3: Multiples and factors

Explanation:

This activity helps children understand multiples and factors. The task involves arranging 12 books into different groups, where each group has the same number of books and no books are left over. This is related to finding the factors of 12, such as 1, 2, 3, 4, 6, and 12, and how 12 can be divided into equal groups without remainder, which is the core concept of multiples and factors.

The least 4-digit number is1000, which is exactly divisible by 8 as 8 × 125 = 1000.

Composite numbers: Numbers having three or more than 3 factors are called composite numbers.

The factors of 106 are 1, 2, 53 and 106.
The factors of 78 are 1, 2, 3, 6, 13, 26, 39 and 78.
The factors of 110 are 1, 2, 5, 10, 11, 22, 55, and 110.
The factors of 66 are 1, 2, 3, 6, 11, 22, 33 and 66.

Multiples of 18 = 18, 36, 54...
Multiples of 6 = 6, 12, 18,...
The first common multiple will be 18 And the next common multiples will be multiples of 18
Hence, first three common multiples of 18, 6 are 18, 36, 54.

The L.C.M. of co-primes is their product.

Let the numbers be 24 and 240.
Then their H.C.F. = 24 and L.C.M. = 240.
Hence the required numbers are 24 and 240.

40, 80 and 100 are multiples of 20.
Hence, we have only three numbers are multiples of 20 from the given list.

8 = 2 × 2 × 2
6 = 2 × 3
14 = 2 × 7
Maximum length be 2m.

Multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27.....
Multiples of 6: 6, 12, 18, 24, 30.....
Multiples of 9: 9, 18, 27.....
The clocks ring in every 18 minutes together.
1st time the clock will ring in 18 minutes, then at 36 minutes and then at 54 minutes.
So in 60 minutes the clocks will ring 3 times.