One day, a father came home from work at 9:00 p.m. Like the previous days, that day was very tiring for him. When he got home he found his 8 year old son who was in grade 2 SD waiting for him at the door of the house. Looks like he's been waiting a long time.

"Why have not you fallen asleep yet?" said the father to his son.

Usually the child is asleep when he comes home from work, and only gets up when he is ready to go to the office in the morning.

"I'm waiting for Papa to come home, because I want to ask how much is Papa's salary?", Said the child.

"Why, don't you think, how come you ask Papa's salary? Do you want to ask for more money? ”Replied the father.

"Ah, no pa, I just ... just want to know ..." said his son.

"Okay, you can count it yourself. Every day Papa works about 10 hours and is paid Rp. 400,000. Each month an average of 25 working days is calculated. So how much is Papa's salary for a month, hey ?! ”Asked the father.

The child then ran to get a paper from the study table while his father...