Playing with Numbers

What is the sum of the first three prime numbers?

The smallest multiple of any number (excluding zero) is:

What is the HCF of $15$ and $25$?

Which of these numbers is divisible by both $3$ and $5$?

Find the HCF of $48, 72$, and $108$.

How many distinct prime factors are there for the number $2,310$?

What is the smallest number having three different prime factors?

Find the greatest number that divides $47, 77,$ and $107$ leaving the same remainder in each case.

What is the LCM of two consecutive odd natural numbers $n$ and $n+2$?

How many prime numbers are there in the range $150$ to $170$?

Which of these numbers is divisible by more than two numbers?

What is the prime number just before $11$?

The sum of the prime numbers $3$ and $11$ is:

Which of these is a composite number ending with the digit $1$?

If $17$ and $19$ are twin primes, what is their sum?

How many composite numbers are there between $1$ and $5$?

Identify the prime number from the following list: $111, 121, 131, 141$.

If the product of two prime numbers is $203$, what is the value of their sum?

What is the sum of all composite numbers between $1$ and $10$?

What is the largest prime factor of the number $510$?

The number $108$ is divisible by $6$ because it is:

The number $832$ is divisible by $8$ because its last three digits ($832$) divided by $8$ gives:

Check the number $4,642$ for divisibility by $11$. The sum of digits at odd places $(2+6=8)$ and even places $(4+4=8)$ have a difference of:

The number $202$ is divisible by $2$ because its ones digit is:

Find the difference between the largest and the smallest digits that can replace $x$ in the number $5,x32$ to make it divisible by $3$.

To check if a large number is divisible by $45$, we can check if it is divisible by which pair of co-prime numbers?

If the number $3,5x4$ is divisible by $8$, and $x$ is a non-zero digit less than $5$, find the value of $x$.

What is the largest 4-digit number of the form $7x4y$ divisible by $55$?

If the 4-digit number $x23x$ is divisible by $2$, $3$, and $5$, what is $x$?

How many 3-digit numbers are divisible by $15$ and $20$?

Identify the full list of common factors of $28$ and $42$.

Which of the following is a common multiple of $5$ and $9$?

What are the common factors of $16$ and $40$?

Which of these is a common multiple of $11$ and $3$?

Calculate the difference between the LCM and the HCF of the numbers $10$ and $15$.

Identify the common factors of the numbers $25$ and $35$.

Determine the Lowest Common Multiple (LCM) of the prime numbers $13$ and $17$.

Find the smallest number which when divided by $35, 45,$ and $55$ leaves remainders $18, 28,$ and $38$ respectively.

Find the number of common factors of $120$ and $180$ that are also perfect squares.

If $G$ is the HCF and $L$ is the LCM of two numbers $18$ and $x$, and given $G=3$ and $L=54$, find the value of $x$.

Which of the following is the prime factorisation of $120$?

Find the prime factorisation of $119$.

Which expression represents the prime factorisation of $118$?

Identify the prime factorisation of $117$.

The prime factorisation of $338$ is:

What is the product of all the distinct prime factors of $130$?

Find the prime factorisation of $234$.

Find the difference between the largest and smallest prime factors of $150$.

Determine the sum of the exponents in the prime factorisation of $1296$.

Find the value of $x$ if $2^2 \times 3^x \times 5 \times 7 = 1260$.

Determine the HCF of $2^2 \times 3$ and $2 \times 3^2$.

What is the HCF of $8, 16$ and $24$?

Find the HCF of $7, 14$ and $28$.

Calculate the HCF of $3, 6$ and $9$.

Find the HCF of $x = 2^2 \times 3^2 \times 5$ and $y = 2 \times 3^3 \times 7$.

Find the HCF of $144, 216,$ and $360$.

Two wooden boards are $120$ cm and $168$ cm long. They are to be cut into planks of equal length as long as possible. What is the length of each plank?

The HCF of three numbers is $104$. If the numbers are $624$, $936$, and $x$, and $x$ is the smallest number between $1000$ and $1100$ divisible by $104$, what is $x$?

Find the greatest number which divides $47$, $95$, and $187$ so as to leave the same remainder in each case.

What is the HCF of $252$ and $594$?

Calculate the LCM of $4, 9,$ and $12$.

What is the LCM of $7$ and $8$?

Calculate the Lowest Common Multiple of $10$ and $100$.

Find the LCM of $4, 6,$ and $12$.

What is the smallest number which when increased by $3$ is exactly divisible by $21, 28,$ and $36$?

Find the smallest number which when decreased by $5$ is exactly divisible by $15, 20,$ and $25$.

Find the LCM of $21, 63,$ and $105$.

Calculate the LCM of $12, 15, 18,$ and $21$.

Find the smallest $4$-digit number which is exactly divisible by $6, 8, 12, 15,$ and $20$.

Find the smallest number which when divided by $15, 20, 25,$ and $30$ leaves remainders $11, 16, 21,$ and $26$ respectively.