Highest Common Factor and Least Common Multiple

 Find the greatest number that divides $690$ and $875$ leaving remainders $10$ and $25$ respectively is -

The greatest $4$-digit number exactly divisible by $10, 15, 20$ is -

Six bells commence tolling together at intervals of $2,4,6,8,10$and $12 \mathrm{seconds}$ respectively. In $30 \mathrm{minutes}$. How many times do they toll together?

Amita, Sneha, and Raghav start preparing cards for all persons of an old age home. In order to complete one card, they take $10$, $16$ and $20$ minutes respectively. If all of them started together, after what time will they start preparing a new card together?

The product of two co-primes is $104$. Their L.C.M. should be:

Find the HCF of $15,27$

Find the HCF of $16,27$

The product of HCF and LCM of two positive numbers is $24$ and the difference between them is $2$. Find the numbers.  

Two numbers are in the ratio $2 : 3$ and their HCF is $13$. Find the LCM of those two numbers. 

Find the HCF of $0.25$ and $0.35$.

What is the HCF of $1.75, 5.6$ and $7$?

Find the HCF of $\frac{8}{7}, \frac{9}{7}, \frac{10}{7}$.

Find the HCF of $\frac{8}{21}, \frac{12}{35}$ and $\frac{32}{7}$.

Find the LCM of $3, 2.7, 0.09$.

Find the least common multiple of $0.36$ and $0.27$.

Find the LCM of $\frac{8}{9}$ and $\frac{4}{9}$.

Find the LCM of $\frac{4}{5}$ and $\frac{3}{7}$.

Find the LCM  of the following by using short cut method:

$10 \text{and} 20$

LCM of $18$,$24$,$42$,$63$ is

Find the HCF of $15$ and $24$ by division method