Let 7- how much is equal to 10 and x, then 7-x = 10. According to the law of mathematical operation, X = 7- 10, and the result is X = 1-3, that is, 7-( 1-3) equals 10.
How to divide a circle into seven equal parts;
Divide the diameter of the circle into 7 equal parts, take 1 to 7, take 7 points 2 as the center and the length of 1 to 7 as the radius, make the arc intersect with the extension line of the horizontal diameter at two points AB, connect two points A and B to each even point 2.4.6 respectively, and extend the intersecting circle to seven points abcdefg, that is, seven points.