1 lakh is indeed equal to 100,000 (100 thousand). In the Indian place value system, numbers are grouped as ones, tens, hundreds, thousands, ten-thousands, lakhs, etc. The assertion and the reason are both correct.
Question 2:
Assertion (A): 9,99,999 is the largest 6-digit number.
Reason (R): Adding 1 to 9,99,999 gives 10,00,000 which is a 7-digit number.
Answer