Question

In one yr, a school uses 12,270 pieces of white paper, 6,670 fewer pieces of blue paper than white paper, and 1,300 fewer pieces of yellow paper than blue paper. How many pieces of paper does the school use in all?

Answer 1

The number of blue paper used is 12,270 - 6,670 = <<12270-6670=5600>>5,600 pieces of blue paper.
The number of yellow paper used is 5,600 - 1,300 = <<5600-1300=4300>>4,300 pieces of yellow paper.
Therefore, the school uses 12,270 + 5,600 + 4,300 = <<12270+5600+4300=22170>>22,170 pieces of paper. Answer: \boxed{22170}.