Question:
The least number that is divisible by all the numbers from 1 to 10 (both inclusive)
(a) 10
(b) 100
(c) 504
(d) 2520
Solution:
(d) Factors of 1 to 10 numbers
$1=1$
$2=1 \times 2$
$3=1 \times 3$
$4=1 \times 2 \times 2$
$5=1 \times 5$
$6=1 \times 2 \times 3$
$7=1 \times 7$
$8=1 \times 2 \times 2 \times 2$
$9=1 \times 3 \times 3$
$10=1 \times 2 \times 5$
$\therefore \quad L C M$ of number 1 to $10=L C M(1,2,3,4,5,6,7,8,9,10)$
$=1 \times 2 \times 2 \times 2 \times 3 \times 3 \times 5 \times 7=2520$