1,3*27+1,3*63+2,3*74+2,3*26 ________________________ 1,8*5,7+1,8*4,3
1,3*27+1,3*63+2,3*74+2,3*26=347; 1. 1,3*27=35,1; 2. 1,3*63=81,9; 3. 2,3*74=170,2; 4. 2,3*26=59,8; 5. 35,1+81,9+170,2+59,8=347 1,8*5,7+1,8*4,3 =18; 1. 1,8*5,7=10,26; 2 1,8*4,3=7,74; 3. 10,26+7,74= 18: 347/18≈20