4 .12 .13 +4 .14 3 +4 4 =1= 3 +4 /∙ 1= 3 = + 4 /− 2 = 4 /: 2 84 = 6 .: C = 1 3 3 /∙ 3 1= AB E = D EB 1+ 3 = 4= / = . . , 50,000 + 100 - 10,000 + 500 - 50,000 + 100 = 10,000 + 500 /−10000 /−100 40,000 = 400 /: 400