Please answer the following question by reasoning step-by-step.
Bobby made a big batch of soup weighing 80 kg. Each day the batch gets reduced by half. How many kg will it reach on the fourth day after he made the soup?

5
On the first day, the soup reduces down to 80 / 2 = 40 kg.

On the second day, it reduces down to 40 / 2 = 20 kg.

On the third day, it is reduced to 20 / 2 = 10 kg.

And on the fourth day, it is finally down to 10 / 2 = 5 kg.

.

Therefore, the answer is 5