Earning of the man in 1 day = Rs 30
Earning of the man in 10 days = Rs 30 × 10
= Rs 300
We do it in the following manner:
1 times 30 is 30.
10 times 30 is 300.
Suppose there are 30 days in a month.
Earning of the man in a month or 30 days = Rs 30 × 30
= Rs 900
We do it in the following manner:
3 times 30 is 90.
30 times 30 is 900.