The HCF and LCM of two numbers are 9 and 270 respectively. If one of the numbers is 45, find the other number.

Find the HCF of 180 and 336. Hence, find their LCM.

Fill in the blanks:

(i) The only natural number which has exactly one factor is ….

(ii) The only prime number which is even is ….

(iii) The HCF of two co-prime numbers is ….

(iv) Two perfect numbers are … and ….

(v) The only prime-triplet is ….

(vi) The LCM of two or more given numbers is the lowest their common …

(vii) The HCF of two or more of given numbers is the highest of their common …

State whether the following statements are true (T) or false (F):

(i) Every natural number has a finite number of factors.

(ii) Every natural number has an infinite number of its multiples.

(iii) There are infinitely many prime numbers.

(iv) The HCF of two numbers is smaller than the smaller of the numbers.

(v) The LCM of two numbers is greater than the larger of the numbers.