Find the area of the shadow part. The answer to question (1) on page 58 of the sixth grade mathematics exercise book

Find the area of the shadow part. The answer to question (1) on page 58 of the sixth grade mathematics exercise book

S=n/360*3.14*r*r
=81.64

Page 55 question 7: as shown in the figure, the length and width of the rectangle are 10 cm and 6 cm respectively. Calculate the area of the shadow part
sorry,
Give the answer in half an hour. It's urgent. It's in volume one

S large fan = n π R / 360 = 2.355cm & sup2;
S small fan = =1.57cm²
10×6=60cm²
60-2.355-1.57≈56cm²

A rational number multiplication problem in the seventh grade mathematics exercise book of people's Education Press
（2+1/2003+1/2004+1/2005)＊（1/2003+1/2004+1/2005+1/2006）-（2+1/2003+1/2004+1/2005+1/2006）＊(1/2003+1/2004+1/2005).

Let 1 / 2003 + 1 / 2004 + 1 / 2005 = a
The original formula is (2 + a) * (a + 1 / 2006) - (2 + A + 1 / 2006) * a
=2a+1/1003+a*a+1/2006*a-2a-a*a-1/2006*a
=1/1003