Question

大正方形的边长为a，小正方形的边长为b，用代数式表示图中阴影部分的面积

199又七分之五*14 简便方法做

Answer 1

（a+b）a-1/2(a+b)b-1/2a²-1/2b(a-b)
=a²+ab-1/2ab-1/2b²-1/2a²-1/2ab+1/2b²
=1/2a²

199又七分之五*14
=(200-2/7)x14
=200x14-2/7x14
=2800-4
=2796