Current location - Training Enrollment Network - Mathematics courses - Elementary school summer homework math problem: A+B a+b+c = 60;; b+ c+d = 70; a+b+d = 80; a+c+d = 90; Find what a.b.c.d is equal to; thank you
Elementary school summer homework math problem: A+B a+b+c = 60;; b+ c+d = 70; a+b+d = 80; a+c+d = 90; Find what a.b.c.d is equal to; thank you
Pupils will also know Baidu, okay? The simplest method

The left and right of the four formulas are added separately, and 3a+3b+3c+3d=300, so a+b+c+d= 100.

Then, for example, to calculate d, subtract the first formula from both sides, and d=40.

Calculate one by one, a=30, b= 10, c=20, d=40.