Question

十一分之七乘十九分之五加十一分之五乘十九分之四简便计算等�

Answer 1

7/11 * 5/19 + 5/11 *4/19
式子是这样吧?
简便计算谈不上,但你可以交换分子,如：
7/11 * 5/19 => 5/11 * 7/19
这样就可以得到：
5/11 * 7/19 + 5/11 *4/19
=5/11 * （7/19 + 4/19）
=5/11 * 11/19
=5/19
交换分子的原理就是乘法交换律,7/11 * 5/19 = (7 * 5)/(11 * 19) => (5 * 7)/(11 * 19)=>5/11 * 7/19

Answer 2

7/11x5/19+5/11x4/19
=5/11x7/19+5/11x4/19
=5/11(7/19+4/19)
=5/11x11/19
=5/19