top 2000 questions

Four positions of a dice are given below. Identify the number at the bottom when top is 6. Question figures:

What value will come in place of question mark(?) in the question (255 xx 2000) div ? xx25 = 2550

What value will come in place of question mark(?) in the question 7 2/7 of ? + 452 = 2000 - 171

In each of the following questions one of the terms in the number series is wrong . Find out the wrong term 20, 40, 200, 400, 2000, 4000, 8000